Perovskites for Optoelectronics

Solar energy

Atomic-level passivation mechanism of ammonium salts enabling highly efficient perovskite solar cells

Essa A. Alharbi et al., Nat. Commun., 10, 3008 (2019) doi:10.1038/s41467-019-10985-5

Various approaches have been developed to push higher the efficiency of halide perovskite solar cells. Here Alharbi et al. show that ammonium salts treatment can reduce the defect density at the perovskite surface and understand the passivation mechanism with 2D-solid state NMR. 

 

Planar perovskite solar cells with long-term stability using ionic liquid additives

Sai Bai et al., Nature, 571, 245–250 (2019) doi:10.1038/s41586-019-1357-2

The rapid rise in power conversion efficiencies for hybrid perovskite solar cells towards those of silicon solar cells has led many to speculate on whether such devices could eventually compete with silicon PV in the market. However, the instability of the hybrid perovskite absorber layer to light, heat, humidity is a serious barrier. Various approaches, including cation substitution, surface treatments and additives, have been used to improve device stability; now Henry Snaith and colleagues have developed an ionic liquid (BMIMBF4) additive approach to improve stability of both unencapsulated and encapsulated planar devices under light soaking conditions. Shareable link

High efficiency perovskite quantum dot solar cells with charge separating heterostructure

Qian Zhao et al., Nat. Commun., 4, 2842 (2019) doi:10.1038/s41467-019-10856-z

Metal halide perovskites have wide tunability in both material and device structure. Here Zhao et al. fabricate heterojunctions of colloidal perovskite quantum dots with different composition using layer-by-layer deposition and demonstrate improved photovoltaic performance with enhanced photocarrier harvesting. 

 

Reduction of lead leakage from damaged lead halide perovskite solar modules using self-healing polymer-based encapsulation

Yan Jianget al., Nat. Energy, 4, 585–593 (2019) doi:10.1038/s41560-019-0406-2

Lead leakage from damaged perovskite solar cells poses a challenge to the deployment of such technology. Here, Jiang, Qiu and co-workers quantify lead leakage caused by a simulated hail impact under a number of weather conditions and show that self-healing encapsulations can effectively reduce it. Shareable link

 

Performance of perovskite solar cells under simulated temperature-illumination real-world operating conditions

Wolfgang Tress et al., Nat. Energy, 4, 568–574 (2019) doi:10.1038/s41560-019-0400-8

Real-world conditions under which solar cells operate can be different from standard testing conditions. Tress et al. investigate the effects of temperature and irradiation on the performance of a perovskite cell and a reference silicon cell, reproducing real weather conditions in the laboratory. Shareable link

 

Controlling competing photochemical reactions stabilizes perovskite solar cells

Silvia Motti et al., Nat. Photon., 13, 532–539 (2019) doi:10.1038/s41566-019-0435-1

The photo-instability of perovskite solar cells is investigated and controlled by the use of a passivation strategy. Shareable link

 

 

Cation and anion immobilization through chemical bonding enhancement with fluorides for stable halide perovskite solar cells

Nengxu Li et al., Nat. Energy, 4, 408–415 (2019) doi:10.1038/s41560-019-0382-6

Defects and defect migration are detrimental for perovskite solar cell efficiency and long-term stability. Li et al. show that fluoride is able to suppress the formation of halide anion and organic cation vacancy defects by restraining the relative ions via ionic and hydrogen bonds. Shareable link

 

Surface passivation of perovskite film for efficient solar cells

Qi Jiang et al., Nat. Photon., 13, 460–466 (2019) doi:10.1038/s41566-019-0398-2

Planar perovskite solar cells that have been passivated using the organic halide salt phenethylammonium iodide are shown to have suppressed non-radiative recombination and operate with a certified power conversion efficiency of 23.3%. Shareable link

 

Efficient, stable and scalable perovskite solar cells using poly(3-hexylthiophene)

Eui Hyuk Jung et al., Nature, 567, 511–515 (2019) doi:10.1038/s41586-019-1036-3

Poly(3-hexylthiophene-2,5-diyl) (P3HT) is a much-loved and much-used stalwart of the semiconducting polymer family. It is used extensively in blends for organic solar cells, but thus far attempts to put it to use as a hole transport material for hybrid perovskite solar cells have resulted in performances well below devices that use spiroOMeTAD, which is expensive and requires dopants. Now, Jangwon Seo and colleagues have developed a deposition approach for hybrid perovksites that results in a double layer of halide perovskite. The top layer of the halide perovskite induces a fibrillar morphology of the top-deposited P3HT and results in greatly improved efficiencies and stabilities to light soaking. Shareable link

Highly stable and efficient all-inorganic lead-free perovskite solar cells with native-oxide passivation

Min Chen et al., Nat. Commun., 10, 16 (2019) doi:10.1038/s41467-018-07951-y

Replacing the toxic lead in the state-of-the-art halide perovskite solar cells is highly desired but the device performance and stability are usually compromised. Here Chen et al. develop inorganic cesium tin and germanium mixed perovskites that show high operational stability and efficiency of 7%. 

 

Efficient two-terminal all-perovskite tandem solar cells enabled by high-quality low-bandgap absorber layers

Dewei Zhao et al., Nat. Energy, 3, 1093–1100 (2018) doi:10.1038/s41560-018-0278-x

Two-terminal monolithic all-perovskite tandem solar cells are attractive due to their flexible nature and low-cost fabrication. Here the authors develop a process to obtain high-quality Sn–Pb perovskite thin films by incorporating chlorine. Such layers are employed to fabricate 20.7%-efficient tandem cells with 80 h operational stability. Shareable link

 

 

From the archive

High irradiance performance of metal halide perovskites for concentrator photovoltaics

Zhiping Wang et al., Nat. Energy, 3, 855–861 (2018) doi:10.1038/s41560-018-0220-2

Metal halide perovskites offer the potential for high-efficiency, low-fabrication-cost solar cells. This study now explores their prospects if deployed in concentrator photovoltaics and finds they perform well up to a concentration of 53 Suns and retain good stability under 10 Suns for over 150 h. Shareable link

 

Visualization and suppression of interfacial recombination for high-efficiency large-area pin perovskite solar cells

Martin Stolterfoht et al., Nat. Energy, 3, 847–854 (2018) doi:10.1038/s41560-018-0219-8

Non-radiative recombination is a critical limiting factor for perovskite solar cell performance. Stolterfoht et al. visualize the various recombination pathways in planar pin cells with photoluminescence imaging and use it to design improved solar cells with 1 cm² areas and ~20% efficiency. Shareable link

 

Suppression of atomic vacancies via incorporation of isovalent small ions to increase the stability of halide perovskite solar cells in ambient air

Makhsud I. Saidaminov et al., Nat. Energy, 3, 648-654 (2018) doi:10.1038/s41560-018-0192-2

Despite their high efficiencies, perovskite solar cells still suffer from degradation issues that impede their practical deployment. Saidaminov et al.  explore the effect of local lattice strain on vacancy formation and show that careful choice of dopants plays a key role, enhancing the device stability. Shareable link

 

Fully textured monolithic perovskite/silicon tandem solar cells with 25.2% power conversion efficiency

Florent Sahli et al., Nat. Mater., 17, 820-826 (2018) doi:10.1038/s41563-018-0115-4

An optimized two-step deposition process allows the formation of uniform layers of metal halide perovskites on textured silicon layers, enabling tandem silicon/perovskite solar cells with improved optical design and efficiency. Shareable link

 

Solvent-controlled growth of inorganic perovskite films in dry environment for efficient and stable solar cells

Pengyang Wang et al., Nat. Commun., 9, 2225 (2018) doi:10.1038/s41467-018-04636-4

Cesium lead iodide inorganic perovskite solar cells have great potential but the phase instability hinders their development. Here Wang et al.  show a controlled drying process to make phase stable and highly efficient solar cells with power conversion efficiency of 15.7%. 

 

Molecular doping enabled scalable blading of efficient hole-transport-layer-free perovskite solar cells

Wu-Qiang Wu et al., Nat. Commun., 9, 1625 (2018) doi:10.1038/s41467-018-04028-8

The existing hole-transporting materials cause problems in the cost and scalability of the perovskite solar cells. Here Wu et al.  fabricate high efficiency cells by molecularly doping the perovskite layer without using hole-transporting layers, thus simplify the device architecture and processing steps.

 

Thermochromic halide perovskite solar cells

Jia Lin et al., Nat. Mater., 17, 261-267 (2018) doi:10.1038/s41563-017-0006-0

CsPbI_3-xBr_x solar cells, which undergo temperature- and moisture-driven reversible transitions between a non-perovskite transparent phase and a perovskite light-absorbing phase, are used as thermochromic photovoltaic devices integrated in windows. Shareable link

 

Tailored interfaces of unencapsulated perovskite solar cells for >1,000 hour operational stability

Jeffrey A. Christians et al., Nat. Energy, 3, 68-74 (2018) doi:10.1038/s41560-017-0067-y

The stability of perovskite solar cells depends on each layer and interface in the device. Here, Christians et al. systematically design the entire device stack focusing on stability, creating cells that retain 88% of their initial efficiency on average, after 1,000 h of unencapsulated operation. Shareable link

 

Systematic investigation of the impact of operation conditions on the degradation behaviour of perovskite solar cells

Konrad Domanski et al., Nat. Energy, 3, 61-67 (2018) doi:10.1038/s41560-017-0060-5

Perovskite solar cells suffer from poor operational stability. Stability measurement conditions used in various studies differ widely. Here, Domanski et al. systematically study environmentally induced degradation in an effort to drive the community towards a consensus on how to age perovskite solar cells. Shareable link

 

Efficient ambient-air-stable solar cells with 2D–3D heterostructured butylammonium-caesium-formamidinium lead halide perovskites

Zhiping Wang et al., Nat. Energy, 6, 17135 (2017) doi:10.1038/nenergy.2017.135

Various strategies are developed to combine high efficiency and stability in perovskite solar cells. Here, Wang et al. mix 2D and 3D mixed-cation and mixed-halide perovskite phases in solar cells with stabilized efficiencies up to 19.5% and improved stability under full illumination and ambient air. Shareable link

 

One-year stable perovskite solar cells by 2D/3D interface engineering

Giulia Grancini et al., Nat. Commun. 8 15684 (2017) doi:10.1038/ncomms15684

Up-scaling represents a key challenge for photovoltaics based on metal halide perovskites. Using a composite of 2D and 3D perovskites in combination with a printable carbon black/graphite counter electrode, Grancini et al., report 11.2% efficient modules stable over 10,000 hours.

 

Diffusion engineering of ions and charge carriers for stable efficient perovskite solar cells

Enbing Bi et al., Nat. Commun. 8, 15330 (2017) doi:10.1038/ncomms15330

Ion migration in perovskite solar cells are known to cause hysteresis and instability. Bi et al., report a charge extraction layer based on graphene, fullerenes and carbon quantum dots which suppresses ion diffusion and enhances charge carrier diffusion leading to efficient devices with improved stability.

 

Low-Bandgap Mixed Tin–Lead Iodide Perovskite Absorbers with Long Carrier Lifetimes for All-Perovskite Tandem Solar Cells

Dewei Zhao et al., Nat. Energy 2, 17018 (2017) doi:10.1038/nenergy.2017.18

All-perovskite tandem solar cells hold the promise of high efficiencies whilst safeguarding the ease of fabrication intrinsic to perovskites. Here, Zhao et al. present a certified 17% efficient tin and lead perovskite solar cell, which is integrated as the low-bandgap component of a tandem device with 21% efficiency. Shareable link

23.6%-efficient monolithic perovskite/silicon tandem solar cells with improved stability

Kevin A. Bush et al., Nat. Energy, 2, 17009 (2017) doi:10.1038/nenergy.2017.9

Perovskite solar cells can complement silicon photovoltaics in multijunction devices. Here, the authors optimize light harvesting in monolithic perovskite-on-silicon devices and fabricate a certified 23.6% efficient, 1 cm2 tandem solar cell with a perovskite device that withstands damp heat tests. Shareable link

 

High-efficiency inverted semi-transparent planar perovskite solar cells in substrate configuration

Fan Fu et al., Nat. Energy 2 16190 (2016) doi:10.1038/nenergy.2016.190

Perovskite solar cells grown in substrate configuration would open a range of applications, if various challenges could be overcome. Towards that aim, Fu et al. present an architecture allowing inverted semi-transparent planar perovskite solar cells with open-circuit voltage of 1.116 V and 16.1% efficiency. Shareable link 

 

Photocatalytic hydrogen generation from hydriodic acid using methylammonium lead iodide in dynamic equilibrium with aqueous solution

Sunghak Park et al., Nat. Energy 2, 16185 (2016) doi:10.1038/nenergy.2016.185

Organometal halide perovskite materials have been the subject of intensive research efforts in the context of photovoltaic applications. Here the authors exploit dynamic equilibrium to photocatalytically generate hydrogen from aqueous HI solutions using methylammonium lead iodide. Shareable link

 

Enhanced efficiency and exceptional stability in hole-transport layer free CsSnI₃ perovskite photovoltaics

K. P. Marshall et al., Nat. Energy, 1, 16178 (2016) doi:10.1038/nenergy.2016.178

Tin-based photovoltaic devices are less toxic than their lead-based counterparts, but suffer severe stability issues due to the susceptibility of tin oxidation. Here the authors report a CsSnI3 perovskite solar cell with a SnCl2 additive that displays a remarkable stability. Shareable link

 

Perovskite solar cells with 18.21% efficiency and area over 1 cm² fabricated by heterojunction engineering

Yongzhen Wu et al., Nat. Energy 1, 16148 (2017) doi:10.1038/nenergy.2016.148

The performance of inverted perovskite solar cells has so far lagged behind that of their normal-structure counterparts. Wu et al. fabricate an inverted perovskite–fullerene solar cell with a graded heterojunction that achieves a certified efficiency of over 18% for a cell area of 1 cm2.  Shareable link

 

 

High-efficiency two-dimensional Ruddlesden–Popper perovskite solar cells

Hsinhan Tsan et al., Nature 536, 512-516 (2016) doi:10.1038/nature18306

Thin-film solar cells were fabricated using layered two-dimensional perovskites with near-single-crystalline out-of-plane alignment, which facilitates efficient charge transport leading to greatly improved power conversion efficiency with technologically relevant stability to light exposure, humidity and heat stress. Shareable link

 

Facet-dependent photovoltaic efficiency variations in single grains of hybrid halide perovskite 

Sibel Y. Leblebici et al., Nat. Energy 1, 16093 (2016) doi:10.1038/nenergy.2016.93

The photovoltaic properties of hybrid organic-inorganic perovskites are sensitive to the local microstructure, but difficult to quantify at the nanoscale. Leblebici et al. use conductive atomic force microscopy to map the local short circuit current and open circuit voltage, finding heterogeneity within individual grains. Shareable link

 

Light-activated photocurrent degradation and self-healing in perovskite solar cells

Wanyi Nie et al., Nat. Commun. 7, 11574 (2016) doi:10.1038/ncomms11574

Organometallic perovskite solar cells exhibit good efficiency but their photo-stability is still relatively poorly understood and controlled. Here the authors show that photo-degradation arises from the formation of light-activated meta-stable trap states, is reversible, and can be frozen at 0ºC.

 

 

Functionalization of perovskite thin films with moisture-tolerant molecules 

Shuang Yang et al., Nat. Energy 1, 15016 (2016), doi:10.1038/nenergy.2015.16

Organic-inorganic perovskites are promising materials for photovoltaic devices, however they have poor tolerance to ambient humidity. It is now shown that their surface can be functionalised with water-resistant molecules to stabilise their performance under humid conditions. Shareable link

 

Improved air stability of perovskite solar cells via solution-processed metal oxide transport layers

Jingbi You et al., Nat. Nanotechnol. 11, 75-81 (2016) doi:10.1038/nnano.2015.230

Using metal oxides for both the hole- and electron-transport layers in perovskite solar cells significantly improves their stability compared with devices containing organic transport layers. Shareable link

 

 

Low-temperature-processed efficient semi-transparent planar perovskite solar cells for bifacial and tandem applications

Fan Fu et al., Nat. Commun. 6, 8932 (2015) doi:10.1038/ncomms9932

Perovskite solar cells already exhibit large efficiencies above 20%. Here, the authors use a low temperature sputtering process to fabricate semi-transparent perovskite solar cells, demonstrating bifacial operation and a 4-terminal tandem with CIGS solar cells surpassing single junction cells. 

 

Flexible high power-per-weight perovskite solar cells with chromium oxide-metal contacts for improved stability in air

Martin Kaltenbrunner et al., Nat. Mater. 14, 1032-1039 (2015) doi:10.1038/nmat4388

The use of a chromium oxide interlayer separating the perovskite film from the metal contacts improves the stability of perovskite solar cells in air. Deposited on thin plastic foils, these ultralight devices power model airplanes and dirigibles. Shareable link

 

Improved performance and stability of perovskite solar cells by crystal crosslinking with alkylphosphonic acid ω-ammonium chlorides

Xiong Li et al., Nat. Chem. 7, 703-711 (2015) doi:10.1038/nchem.2324

Perovskite materials show great promise for solar cell devices, owing in particular to their high power conversion efficiency. Now, the addition of butylphosphonic acid 4-ammonium cations during a one-step process has been shown to improve both the efficiency and moisture stability of perovskite photovoltaics, through the formation of hydrogen-bonding crosslinks between neighbouring grains. Shareable link

 

Perovskite–fullerene hybrid materials suppress hysteresis in planar diodes

Jixian Xu et al., Nat. Commun. 6, 7081 (2015) doi:10.1038/ncomms8081

Metal halide perovskites are promising for solar energy harvesting, but currently prone to a large hysteresis and current instability. Here, Xu et al. show improvements in a hybrid material in which the fullerene is distributed at perovskite grain boundaries and thus passivates defects effectively.