Enhanced Performance Of Perovskite Solar Cells By Introduction Of PCBM

Perovskite solar cells(PSCs)has attracted widespread attention owing to their excellent photoelectric performance,such as high efficiency,low cost and simple process.The PSCs architecture consists of ITO,electron transport layer(ETL),perovskite,hole transport layer(HTL),electrode.At present,there are still many problems that need to be resolved in perovskite solar cells,for example,the hysteresis effect and stability,etc.Several methods to solve the above problems have been developed,including interface modification between the ETL and perovskite layer,doping in the active layer to enhance the crystallinity of perovskite and finding new absorbent lead-free perovskite materials.In this thesis,we focused our work on enhancing the PCE of n-i-p type PSCs by introducing PCBM materials into the Perovskite solar cells,and the main works are as follows:(1)A thin PCBM layer was introduced between TiOx ETL/perovskite by spin-coating the PCBM solution(10 mg/ml)to modify the interface.The obtained results show that PCBM material as the interface modification layer can improve the photoelectric performance of the PSCs.The PCBM interface modification layer plays an important role in the ETL surface defects passivation.Then it can reduce the recombination rate between the ETL and perovskite layer,contributing to the improvement of the PSCs' conversion efficiency(PCE).In addition,PCBM is good electron transport material,thus promoting the transport and the extraction of electrons in the interface between ETL and perovskite active layer.(2)PCBM was doped in perovskite active layer,resulting in the efficiency enhancement of PSCs.The PCE and the filling factor(FF)were also improved.The PCE of PSCs is enhanced from 13%to 16.5%,and FF is enhanced from 63%to 70%.According to the scanning electron microscope(SEM)imiages,we can observe that it can improve the quality of perovskite film and the electron transport performance to dope PCBM material into the perovskite layer.During the crystallizing process,PCBM can fill and decrease the defects between perovskite grains,reducing the recombination through these defects.