Low-cost encapsulation technology leads to limited protection against oxygen and water. Therefore, a proper and powerful encapsulation is necessary to further improve the device stability. Encapsulation of alternating inorganic-organic multilayer actually serves as a high barrier, fulfilling the requirements for flexible OPVs. The encapsulating layer should be possessed with easy process, light weight, no defects, and flexibility.
In summary, all the factors influencing device stability should be emphasized in order to prolong device lifetime and achieve commercial products. Taking various interface parameters and factors into account, a much more comprehensive model should be established by improving previous models mentioned before. Deep insight and knowledge into degradation mechanism, which could disclose the relationship between degradation mechanisms and material design, preparation technique, heat effect during operation, annealing treatment, and encapsulation, are significantly beneficial to optimization of organic material design and device stability.