High efficiency polymer solar cells sensitized by red-emitting ZnCuInS nanoplatelets

We synthesized the two-dimensional Zn–Cu–In–S (ZCIS) semiconductor nanoplatelets and then modified their surface with 4-bromobenzenediazonium tetrafluoroborate. The surface modified ZCIS nanoplatelets were combined with the conventional photovoltaic hole transport layer material (HTL) PEDOT: PSS. The work function of the HTL increased from 5.04 eV to 5.17 eV, thus promoting the reduction of the energy potential barrier and increasing the internal electric field. It also effectively improves the light utilization by effectively increasing the absorption of light in the spectral range below 500 nm and converting them into the secondary emission in the 600–700 nm range. Such emission can be effectively utilized by the active layer to increase the open-circuit voltage (Voc) and short-circuit current (Jsc) of the cell, resulting in an increase in the overall cell power conversion efficiency (PCE) from 12.29%–13.14%.