Cross-Linkable, Solvent-Resistant Fullerene Contacts for Robust and Efficient Perovskite Solar Cells with Increased J SC and V OC

• Published in: ACS applied materials & interfaces Vol. 8; no. 39; pp. 25896 - 25904
• Main Authors: Watson, Brian L, Rolston, Nicholas, Bush, Kevin A, Leijtens, Tomas, McGehee, Michael D, Dauskardt, Reinhold H
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 05.10.2016
• Subjects: solvent resistance; electron transport material; perovskite solar cells; reliability; fracture
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.6b06164

The active layers of perovskite solar cells are also structural layers and are central to ensuring that the structural integrity of the device is maintained over its operational lifetime. Our work evaluating the fracture energies of conventional and inverted solution-processed MAPbI3 perovskite solar cells has revealed that the MAPbI3 perovskite exhibits a fracture resistance of only ∼0.5 J/m2, while solar cells containing fullerene electron transport layers fracture at even lower values, below ∼0.25 J/m2. To address this weakness, a novel styrene-functionalized fullerene derivative, MPMIC 60 , has been developed as a replacement for the fragile PC61BM and C60 transport layers. MPMIC 60 can be transformed into a solvent-resistant material through curing at 250 °C. As-deposited films of MPMIC 60 exhibit a marked 10-fold enhancement in fracture resistance over PC61BM and a 14-fold enhancement over C60. Conventional-geometry perovskite solar cells utilizing cured films of MPMIC 60 showed a significant, 205% improvement in fracture resistance while exhibiting only a 7% drop in PCE (13.8% vs 14.8% PCE) in comparison to the C60 control, enabling larger V OC and J SC values. Inverted cells fabricated with MPMIC 60 exhibited a 438% improvement in fracture resistance with only a 6% reduction in PCE (12.3% vs 13.1%) in comparison to those utilizing PC61BM, again producing a higher J SC.