Dithiol treatments enhancing the efficiency of hybrid solar cells based on PTB7 and CdSe nanorods

We report the fabrication of polymer/inorganic hybrid solar cells （HSCs） based on CdSe nanorods （NRs） and the semiconducting polymer PTB7. The power conversion efficiency of HSCs can be significantly enhanced by engineering the polymer/nanocrystal interface with ethanedithiol （EDT） and 1,4-benzenedithiol （1,4-BDT） treatments and reached 2.58% and 2.79%, respectively. These results were preferable to that of a pyridine-coated NR-based device （1.75%）. This improvement was attributed to the thiol groups of EDT and 1,4-BDT, which can tightly coordinate the Cd ions to form Cd-thialate on CdSe NR surfaces, thereby effectively passivating the NR surface and reducing the active layer defects. Therefore, the rate of exciton generation and dissociation was enhanced and led to the improvement of the device performance.