A Homopolymer of Xanthenoxanthene-Based Polycyclic Heteroaromatic for Efficient and Stable Perovskite Solar Cells

Highly efficient perovskite solar cells typically rely on spiro-OMeTAD as a hole transporter, achieving a 25.7 % efficiency record. However, these cells are susceptible to harsh 85 degrees C conditions. Here, we present a peri-xanthenoxanthene-based semiconducting homopolymer (p-TNI2) with matched energy levels and a high molecular weight, synthesized nearly quantitatively through facile oxidative polymerization. Compared to established materials, p-TNI2 excels in hole mobility, morphology, modulus, and waterproofing. Implementing p-TNI2 as the hole transport layer results in n-i-p perovskite solar cells with an initial average efficiency of 24.6 %, rivaling 24.4 % for the spiro-OMeTAD control cells under identical conditions. Furthermore, the p-TNI2-based cells exhibit enhanced thermostability at 85 degrees C and operational robustness. A semiconducting homopolymer, hailing from an electron-rich peri-xanthenoxanthene-based polycyclic aromatic monomer, produces uniform films with heightened hole mobility, amplified modulus, and constrained species diffusion. These attributes enable the construction of perovskite solar cells with an initial average efficiency of 24.6 %, which also exhibit enhanced thermostability at 85 degrees C and operational durability.image

Automated summary

Researchers have improved the performance of perovskite solar cells by synthesizing a new material called p-TNI2. Compared to traditional materials, p-TNI2 has advantages in terms of carrier mobility and thermal stability, while achieving a similar high efficiency.