Amino‐Functionalized Graphdiyne Derivative as a Cathode Interface Layer with High Thickness Tolerance for Highly Efficient Organic Solar Cells

Efficient cathode interfacial materials (CIMs) are essential components for effectively enhancing the performance of organic solar cells (OSCs). Although high‐performance CIMs are desired to meet the requirements of various OSCs, potential candidates for CIMs are scarce. Herein, an amino‐functionalized graphdiyne derivative (GDY‐N) is developed, which represents the first example of GDY that exhibits favorable solubility in alcohol. Utilizing GDY‐N as the CIM, an outstanding champion PCE of 19.30% for devices based on the D18‐Cl:L8‐BO (certified result: 19.05%) is achieved, which is among the highest efficiencies reported to date in OSCs. Remarkably, the devices based on GDY‐N exhibit a thickness‐insensitive characteristic, maintaining 95% of their initial efficiency even with a film thickness of 25 nm. Moreover, the GDY‐N displays wide universality and facilitates exceptional stability in OSCs. This work not only enriches the diversity of GDY derivatives, but also demonstrates the feasibility of GDY derivatives as CIMs with high thickness tolerance in OSCs. An amino‐functionalized graphdiyne derivative (GDY‐N), with its high conductivity, appropriate LUMO energy level, and good solubility in alcohols, emerges as a remarkable cathode interlayer material. An impressive power conversion efficiency (PCE) of 19.30% is achieved for D18‐Cl:L8‐BO‐based devices (certified result: 19.05%). This value is one of the highest reported for OSCs to date.