The structure of experimentally designed solar cells was optimized in terms of the photoactive layer thickness for both organic bulk heterojunction and hybrid perovskite solar cells. The photoactive layer thickness had a totally different behavior on the performance of the organic and hybrid solar cells.
Optimization also partially helps in improving the cells stability. The thickness of each layer is varied while keeping thickness of other layers constant i.e., if the thickness optimization of perovskite layer is carried out then the thickness of the ETL, HTL and FTO is kept constant.
Light harvesting as well as the density of generated excitons in the PAL vary along the layer thickness, which affects the short-circuit current (Jsc) and in consequence the power conversion efficiency (PCE). Optimization of the functional layer thickness is therefore one of the routes to increase the PCE 3, 4, 7, 20.
In the present work, optimization of individual layers of cell which is the most vital designing parameter of a perovskite solar cell is undertaken . As the cell performance totally depends upon the perovskite layer morphology, the optimization of the thickness of the perovskite layer plays a vital role .
The thickness variation of electron-transport layer (ETL) (TiO 2) not affect the cell parameters much i.e., throughout the variation of thickness the cell parameters remain constant, because all the process related to excitons takes place in the absorber/perovskite layer of the cell .
Solar cells (SC) designed here are based either on an organic or an hybrid photoactive layer (PAL), with the structure: ITO (indium tin oxide) on glass (anode)/ hole transporting layer (HTL)/ photoactive layer (PAL)/ electron transporting layer (ETL) / Al (cathode).