Side chain modulated carbazole-based bifunctional hole-shuttle interlayer simultaneously improves interfacial energy level alignment and defect passivation in high-efficiency perovskite solar cells
Perovskite solar cells have reached a power conversion efficiency
over 26.1 %, and the interface engineering between perovskite and hole
transport layer (HTL) is crucial for achieving high performance. There
exists a noticeable research gap when it comes to designing an
interlayer layer that can both hold defect passivation and hole
transportability. To bridge this gap, we have designed and synthesized
two functional molecules with carbazole cores and side chain modifications, namely CVE-Br and CVE-DPA. Beyond
the suitable energy levels of the carbazole group, CVE-Br can
intercalate into perovskite lattice, create a low-dimensional
perovskite, and further minimize defects. Instead of forming low
dimensional structure, CVE-DPA molecule wraps around the perovskite.
That makes it passivate perovskite defects and facilitate hole transport
without the limitation of carrier transportation. As a result, the
power conversion efficiency of perovskite solar cells with CVE-DPA can achieve 22.05 %. The hydrophobicity of CVE-DPA confers
the corresponding devices to retain 87 % of the initial efficiency
after 1000 h.
