Ultra‐Planar Polymer Hole Transport Materials via Bridging‐Atom Engineered Noncovalent Conformational Locking for High‐Performance Perovskite Photodetectors and Neuromorphic Computing
Longni Chen, Huiqing Hou, Jiahao Cui, Zewang He, Ran Yang, Xiaojie Zhang, Shougen Yin, Zhiqiang Jiao, Yan Lu, Xiaoming WuABSTRACT
Developing efficient dopant‐free polymer hole transport materials (HTMs) plays a crucial role in solution‐processed perovskite optoelectronics. Herein, we propose a conjugated backbone‐integrated noncovalent conformational locking (NCL) strategy and report three p‐type conjugated polymers (PTPC, PTPN, and PTPSi) via bridging atom engineering. The backbone‐integrated NCL outperforms conventional side‐chain‐based noncovalent interactions, enabling a highly planarized polymer conformation and more compact π – π stacking. Notably, the strategic incorporation of dual‐functional N atoms in PTPN strengthens intramolecular S···N interactions, which minimizes molecular reorganization energy and boosts hole mobility. Meanwhile, thiophene S and bridging N atoms synergistically anchor undercoordinated Pb 2 + on the perovskite surface, thus effectively suppressing defect‐induced nonradiative recombination. Three polymers were evaluated as dopant‐free HTMs in all‐solution‐processed perovskite photodetectors. The PTPN device presents an extremely low dark current density of 3.25 × 10 − 10 A cm − 2 at 0 V, an outstanding external quantum efficiency (EQE) of 86.1%, and a high detectivity exceeding 10 12 Jones. In addition, the multifunctional PTPN device exhibits stable and reconfigurable synaptic plasticity, offering extensive features for synaptic behavior emulation, visual memory, and high‐accuracy image recognition. We also demonstrate an advanced preprocessing strategy, and proof‐of‐concept preprocessing with the PTPN device achieves an ultrahigh recognition accuracy of 97.7% in an artificial neural network.