Utilizing non-conjugated small-molecular tetrasodium iminodisuccinateas electron transport layer enabled improving efficiency of organic solar cells

Interfacial engineering plays a key role in the performance enhancement of organic solar cells (OSCs), which has a significant impact on the charge collection and transport in the devices. Herein, the conventional devices based on PTB7-Th:PC71BM were prepared by introducing a non-conjugated small molecule tetrasodium iminodi-succinate (IDS) as an electron transport layer (ETL). It is shown that IDS as ETL improves the charge transfer and collection and simultaneously inhibits the charge recombination in the devices. Consequently, the optimal power conversion efficiency (PCE) of the device with IDS as ETL reaches up to 9.45%, with an open circuit voltage (V-OC) of 0.80 V, a short circuit current density (J(SC)) of 16.88 mA cm(-2) and a fill factor (FF) of 70.01%. This work provides a new approach to optimize the PCEs of the OSCs.