High‐Performance All‐Polymer Photoresponse Devices Based on Acceptor–Acceptor Conjugated Polymers

Abstract

Three acceptor–acceptor (A–A) type conjugated polymers based on isoindigo and naphthalene diimide/perylene diimide are designed and synthesized to study the effects of building blocks and alkyl chains on the polymer properties and performance of all‐polymer photoresponse devices. Variation of the building blocks and alkyl chains can influence the thermal, optical, and electrochemical properties of the polymers, as indicated by thermogravimetric analysis, differential scanning calorimetry, UV–vis, cyclic voltammetry, and density functional theory calculations. Based on the A–A type conjugated polymers, the most efficient all‐polymer photovoltaic cells are achieved with an efficiency of 2.68%, and the first all‐polymer photodetectors are constructed with high responsivity (0.12 A W−1) and detectivity (1.2 × 1012 Jones), comparable to those of the best fullerene based organic photodetectors and inorganic photodetectors. Photoluminescence spectra, charge transport properties, and morphology of blend films are investigated to elucidate the influence of polymeric structures on device performances. This contribution demonstrates a strategy of systematically tuning the polymeric structures to achieve high performance all‐polymer photoresponse devices.

Recent Progress on Photomultiplication Type Organic Photodetectors

“…The common configurations of photodiodes can be categorized as the conventional and inverted type, in which the presence of interface layers is considered to effectively reduce the dark current for obtaining high detectivity, accompanied by low noise equivalent power (NEP) and large linear dynamic range (LDR). For photodiodes based on photovoltaic effect, an absorbed photon can generate at best one electron‐hole pair, resulting in the EQE of <100% . The collection of photogenerated carriers is assisted by the built‐in potential in the junction, which results from different work functions between anode and cathode.…”

Imide‐Functionalized Polymer Semiconductors

“…Two A‐A type polymers 5 a and 5 b with distinct 2‐ethylhexyl and 2‐octyldodecyl chains on the PDI unit were synthesized by Huang et al., and the D1 : 5 b blend film showed a rougher but continuous interpenetrating network than that of D1 : 5 a . Inverted OSCs with a device structure of indium tin oxide (ITO)/ZnO/blend film/MoO 3 /Ag showed a PCE of 2.68 %, which was the highest efficiency for all‐PSCs with A‐A type polymers as acceptors at that time . The performance is likely limited by the twisted backbone as a result of the linkage between PDI and isoindigo.…”

Diketopyrrolopyrrole‐based polymer fibrils formation by changing molecular conformation during film formation

“…The planarization conformation could be tuned by (1) increasing electronic delocalization of the molecular backbone, (2) decreasing the steric hindrance of the side chain, (3) restricting the torsion of the molecular backbone, and (4) improving the ability of adjusting conformation using annealing techniques . Alternatively, the planarization conformation can be tuned during the film formation process using solvent additives, which is the primary focus of the current study.…”