# Progress in Improving Photovoltaics Longevity
## 5 Discussion
LID can be significantly restricted by ensuring enhanced stability and quality control in the initial phase of manufacturing. Longevity and highly efficient performance can be achieved by developing optimized system designs that mitigate high system voltages and eliminate extreme thermal stresses. Research targeted to organic and perovskite solar cells is more demanding. Advanced encapsulation techniques are of foremost importance in shielding these high-sensitive materials from environmental agents. Additionally, the development of thermally stable polymers and improved UV-blocking layers can prove to be valuable allies in mitigating heat and UV irradiance exposure, respectively. Especially for the OPVs, new organic materials with enhanced properties, advanced stability, and high-flexibility barrier coatings are being designed and constructed to address the multiple degradation challenges. Based on the theory presented in Section 3 and according to Equation (9), the failure time of a PV module is inversely proportional to the physical degradation rate. Due to the dynamic form of the environmental conditions, namely transient solar irradiance, fluctuations in temperature, and variable humidity content, physical degradation includes the total effect of thermo-mechanical, hydrolysis, and photo-degradation rates. Extending the lifespan of PV modules requires the reduction of these factors' contribution as much as possible. To enhance both PV module power output and solar cell service lifetime, advanced cooling methods need to be developed in order to maintain the internal cell temperature at low values. Defining an economical, profitable, attainable, and practically applicable cooling method across various climatic features remains a demanding challenge. Among other passive cooling techniques, radiative cooling [212] is an appealing method as heat dissipation to the environment and outer space requires no additional energy or material support. Due to its simplicity, economic viability, and great perspectives, efficient thermal management of PV modules through radiative cooling has begun to monopolize the scientific interest. However, several obstacles still need to be overcome, and further research in this direction remains essential. For typical c-Si solar cells, electron excitation occurs when the energy of the incident photons surpasses the semiconductor bandgap (Eg \(\approx\) 1.1 eV for Silicon). In contrast, energy below the bandgap is converted into heat, resulting in an increase in the cell temperature. Consequently, reduction in sub-bandgap absorption is vital for ensuring effective radiative cooling. An optimized solution for thermal management and extended lifetime for PV systems is the proper combination of eliminated sub-bandgap absorption and radiative cooling. Alongside effective heat dissipation, impactful management of the hydrolysis rate is also beneficial. Hydrolysis is a chemical reaction activated by moisture, which deteriorates the polymer layers and structure of the PV module. A seemingly successful way to mitigate hydrolysis is the incorporation of innovative hydrophobic materials for coatings and encapsulants. These materials, which include water-resistant coatings and fluoropolymers, significantly limit the entry of moisture and water by offering a protective barrier. This approach can be profitable for the module's performance and operational lifetime, especially in wet and humid areas. Local climate conditions affect the performance operation of solar cells and can reduce up to 70% of the output in harsh environments of high temperatures and relative humidity [213]. This result is mainly related to temperature increase as an intrinsic PV parameter and less related to humidity effect due to water vapor condensation at the PV front surface, the reflection of incident radiation, or the reduction of the direct and the increase of the diffuse component of solar radiation in a humid climate.