The heat dissipation has been rarely investigated in solar cells although it has a significant impact on their performance and reliability. For the first time, an extended three-dimensional (3-D) simulation of heat distribution in perovskite solar cells is presented here. We use COMSOL Multiphysics to investigate the temperature distribution in conventional perovskite solar cells through a coupled optical–electrical–thermal modules. Wave optics module, semiconductor module, and heat transfer in solid module are coupled in COMSOL Multiphysics package to perform the simulation in 3-D wizard. The electrical behavior, optical absorption, and heat conduction or convection are considered to gain insight into heat dissipation across the cell. The simulation results suggest that the heat produced in the cell is best dissipated from the metallic contact where the PbI $_2$ defect forms because of oxidation or decomposition of the perovskite layer at moisture exposure. The generated heat varies significantly from the front FTO contact to bottom metallic electrode. The more heat dissipation and accumulation is observed at the junction and electrode sides too. In our simulations, we consider the Joule heating, nonradiative recombination heating, and heat flux in every layer of the cell and calculate the carrier’s concentration, electric field distribution, Joule heating, Shockley–Read–Hall heating, total heat flux, and temperature distribution across the solar cell structure. The simulations reveal that the metallic contact must be selected as a highly heat conductive material in order to accelerate the heat dissipation on the bottom of the cell and to enhance the cell reliability against temperature increase under normal operation.

The Cu $_2$ ZnSnS $_x$ Se $_{4-x}$ (CZTSSe) thin-film solar cells have attracted the attention of researchers due to its earth-abundant composition containing Copper, Zinc, Tin and Sulfur, and Selenide with 12.6% record efficiency (2013-IBM). A 3-D simulation analysis is presented here on the optical, electrical, and thermal characteristics of CZTSSe solar cell using COMSOL multiphysics 3-D simulation package. COMSOL is capable of calculating the optical–electrical–thermal models through electromagnetic wave, semiconductor, and heat transfer modules for a finely meshed structure. Using this capability, we have calculated the optical photogeneration rate of the a Mo/Mo(S,Se) $_2$ /CZTSSe/CdS/ZnO/ITO/air structure by inserting the refractive index and extinction coefficient of every layer in Wave optic module in COMSOL. We also calculated the total optical generation rate for two structures with and without Mo(S,Se) $_2$ layer at the junction of Mo and CZTSSe layers. The current–voltage curve, electric field profile, and the recombination rate of the cell has also been calculated by Semiconductor module coupled to wave optic module. The current–voltage characteristics show an improvement in $V_{\text{oc}}$ for the cell with Mo(S,Se) $_2$ layer (0.46 to 0.513 V) which was also suggested by IBM for a record cell efficiency. Finally, the thermal maps of the cell has been calculated by heat transfer module coupled to semiconductor module considering the Shockley–Read–Hall (SRH) recombination heat, Joule Heat, and conductive heat flux. The total heat flux magnitude of the cell was also mapped as a result out of these heat generation and cooling sources. The SRH heat is maximum within the depletion width at the CZTSSe/CdS interface, whereas the Joule heating is intensive at the Mo/Mo(S,Se) $_2$ /CZTSSe side. Interesting is to see that the heat is mainly conducted to environment from Mo side presented by the conductive heat map. The total heat flux is intensive at both top and bottom interfaces which means the heat is generated at both top and bottom sides of the cells and not only from the illuminated part.

The development of environmentally friendly materials has been the focus of many research groups in recent years due to increased harmful effects of plastics on the environment. Bio-based materials are considered a key solution from a sustainable manufacturing perspective. The nano-coating of biopolymer blends with silver nanoparticles is the subject of challenging research projects in line with the EU Directive on environment protection and sustainable manufacturing. Coating biopolymers with silver nanoparticles provides an antimicrobial and antiviral active surface. In this work, we develop silver nanoparticle-coated biopolymer Arboblend V2 Nature pellets. The main goal is to obtain a new material with antibacterial action obtained from the blending of a biopolymer pellets with silver nanoparticles through physical vapor deposition. The study is divided in three steps. The first step represents the silver nano-coating of the Arboblend V2 Nature and the characterization of the coated/raw pellets. The second step involves the injection molding of the silver nano-coated pellets and the characterization of the samples obtained. The last step regards the press molding of the coated pellets in order to obtain thin films, as well as their characterization. The PVD-sputtering technique is used to coat the pellets with silver nanoparticles. This process is especially optimized for coating raw materials with high water content and small-size pellets. The mechanical properties, surface chemical composition and the thermal properties of the both virgin and silver nanoparticle-coated biopolymer pellets are measured and analyzed for mechanical and thermal resistance of the nano-coating layer. Differential scanning calorimetry, scanning electron microscopy, X-ray photoemission spectroscopy and nanoindentation mechanical testing is performed. The calorimetry test detects no significant alteration of the biopolymer produced from the PVD process and confirms the optimized PVD process for nano-coating of the Arboblend V2 Nature pellets with a viable application in nano-silver–biopolymer composite products.