Wenqiang Qiao

In situ switching layer-by-layer assembly: one-pot rapid layer assembly via alternation of reductive and oxidative electropolymerization

In situ one-pot rapid layer-by-layer assembly of polymeric films as an active layer of a photoactive device via alternation of reductive and oxidative electropolymerization has been demonstrated. This novel fabrication without moving or changing experimental gears would be a powerful strategy to develop automated layer-by-layer machines.

Advances in Organic Near-Infrared Materials and Emerging Applications

Much progress has been made in the field of research on organic near-infrared materials for potential applications in photonics, communications, energy, and biophotonics. This account mainly describes our research work on organic near-infrared materials; in particular, donor-acceptor small molecules, organometallics, and donor-acceptor polymers with the bandgaps less than 1.2 eV. The molecular designs, structure-property relationships, unique near-infrared absorption, emission and color/wavelength-changing properties, and some emerging applications are discussed.

Side-chain engineering in naphthalenediimide-based n-type polymers for high-performance all-polymer photodetectors

A series of n-type semiconducting conjugated polymers based on naphthalene diimide (NDI) having three different side chains, 5-decylpentadecyl, 2-octyldodecyl and 4-(2-octyldodecyloxy)phenyl, were synthesized. Experimental results showed that the subtle structural changes at the side chains can influence the molecular packing, electron mobility, blend film morphology and thus performance of bulk-heterojunction polymer photodetectors using these NDI-based polymers as acceptors. The optimized all-polymer photodetector exhibited a specific detectivity (D*) of over 1013 Jones in the spectral region of 300–800 nm under −0.1 V bias, which is among the best D* values of the reported UV–vis–NIR all-polymer photodetectors and comparable to the best fullerene-based photodetectors.

Low-LUMO acceptor polymers for high-gain all-polymer photodiodes

In this work, we report three acceptor polymers with low levels of lowest unoccupied molecular orbital (LUMO) energies and studies on all-polymer photodiodes. By employing these polymers as electron acceptors and PTB7-Th as electron donors, we prepared all-polymer photodiodes that exhibited a high gain in external quantum efficiency (EQE) and high detectivity. In particular, P3-based devices showed EQE over 40u2006000%, responsivity over 110 A W−1 and a specific detectivity of 3.5 × 1014 Jones, representing the best result of all-polymer photodiodes reported to date. Our work has demonstrated that high gain all-polymer photodiodes could be readily achieved by using appropriate interlayers and low-LUMO acceptor polymers.