Improving the stability and efficiency of polymer solar cells by γ‐radiated graphitic carbon nitride
Inzamam Nawas Nawas Mumthas, Mohamad Firdaus Mohamad Noh, Nurul Affiqah Arzaee, Nurul Aida Mohamed, Siti Nur Farhana Mohd Nasir, Hussain Alessa, Aznan Fazli Ismail, Hazim Moria, Mohd Asri Mat Teridi
Abstract
Graphitic carbon nitride (g-C3N4) is a potential additive that can alter the polymer solar cells (PSC) performance. Hereby, we report a novel strategy by applying γ-radiated g-C3N4 as additive into bulk heterojunction polymer solar cell (BHJ-PSC). The incorporation of γ-radiated g-C3N4 into the active layer P3HT:PC61BM augments the efficiency of BHJ-PSC by more than half with respect to the standard undoped device counterpart. The increased performance of γ-radiated g-C3N4-doped BHJ-PSC is related to increased surface roughness, higher crystallinity, greater optical absorption of the polymer layer and improved charge transfer/recombination dynamics within the device. The optimized BHJ-PSC containing γ-radiated g-C3N4 without encapsulation reaches 2.4% power conversion efficiency (PCE) and the device also retains 60% of the initial PCE even after exposure to high humidity condition (relative humidity 40%-70%) for 30 days. This suggests that γ-radiated g-C3N4 is capable of preventing moisture and oxygen-induced degradation of P3HT:PC61BM. The γ-radiated g-C3N4 additive is also employed in PBDTTT-C:PCBM polymer system which demonstrates the champion PCE of 2.9%. The present work not only provides an effective strategy for simultaneously enhancing the efficiency and stability of BHJ-PSC, but also opens up a new horizon for radiation technology and additive engineering.