a,b, Six types of devices with different Pb-absorber layer coating and device damage conditions were tested. All devices were sealed by EVA film on the back metal-electrode side. The details of Pb-absorber coating and device-damage conditions are given in the table on the right. Six devices for each type of sample were tested. The Pb-leakage tests were conducted at room temperature (a) and 50 °C (b) by soaking each damaged device in 40 ml of water. The error bars represent the standard deviations from six samples of each type of device. It is worth noting that the case with both sides coated and damaged outperforms the case with only one side (particularly the back side) coated and damaged. This effect can be attributed to the chemical Pb-sequestrating nature of the DMDP and EDTMP–PEO films, which yields a summed sequestration effect, namely any aqueous Pb chemically captured by the Pb-sequestrating layer on one side will no longer flow back to the other side, hence, reducing the leaked Pb via either side compared with the case where a coating layer is present on only one side.