Highly efficient near-infrared hybrid perovskite solar cells by integrating with a novel organic bulk-heterojunction

Extending photoelectric response to near-infrared region (NIR) has become an urgent subject for the research of perovskite solar cells (PSCs). However, it is still a challenge due to the shortage of matching NIR photovoltaic materials and device structure. The rapid development of NIR organic photovoltaic materials and devices (OPVs) in recent years offers new opportunity for developing such PSCs. Herein, to broaden the photoresponse of PSCs, a novel PBDB-TF: BTP-4Cl bulk-heterojunction (BHJ) organic layer was successfully integrated on the PSCs, which extended the photoresponse of the device to 950 nm. And more, to boost the utilization of NIR light, the Au nanorods (Au NRs) were introduced into the organic BHJ layer through localized surface plasmon effect (LSPR). To further improve the device stability and satisfy solution competition, the MoO3 was fabricated as hole transport layer substituting traditional Spiro-OMeTAD. After adopting such a device, the power conversion efficiency (PCE) was increased significantly from 16.67% to 21.55%, which was the optimum among the reported organic/perovskite hybrid solar cells and the devices employing MoO3 as the hole transport layer. The illumination and humidity stability of the perovskite/organic/noble metal integrated solar cells were also significantly improved. The devices under standard sunlight irradiation for 1000 h maintained more than 70% of initial PCE. This work demonstrates that the perovskite/organic/noble metal integrated structure is a novel and powerful approach to obtain efficient and stable NIR-harvesting PSCs.