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1.
Nat Commun ; 12(1): 178, 2021 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-33420010

RESUMO

Tandem organic solar cells are based on the device structure monolithically connecting two solar cells to broaden overall absorption spectrum and utilize the photon energy more efficiently. Herein, we demonstrate a simple strategy of inserting a double bond between the central core and end groups of the small molecule acceptor Y6 to extend its conjugation length and absorption range. As a result, a new narrow bandgap acceptor BTPV-4F was synthesized with an optical bandgap of 1.21 eV. The single-junction devices based on BTPV-4F as acceptor achieved a power conversion efficiency of over 13.4% with a high short-circuit current density of 28.9 mA cm-2. With adopting BTPV-4F as the rear cell acceptor material, the resulting tandem devices reached a high power conversion efficiency of over 16.4% with good photostability. The results indicate that BTPV-4F is an efficient infrared-absorbing narrow bandgap acceptor and has great potential to be applied into tandem organic solar cells.

2.
ACS Appl Mater Interfaces ; 11(36): 33515-33524, 2019 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-31423760

RESUMO

In this work, a novel back contact interface engineering is developed for inverted planar perovskite solar cells, in which a tetrafluoroterephthalic acid (TFTPA) interlayer is inserted between CH3NH3PbI3 and PC61BM to strengthen the interface contact. Benefiting from the strong Coulombic interactions between positive electron-poor tetrafluoroterephthalate moieties and negative electron-rich fullerene molecules, as well as the coordinate effect between -COOH groups of TFTPA and Pb2+ ions of perovskites surface, a tightly jointing and defect-passivated CH3NH3PbI3/PC61BM interface is formed. The strengthened CH3NH3PbI3/PC61BM back contact can significantly facilitate electron transport and simultaneously diminish the charge accumulation and recombination. Therefore, power conversion efficiency (PCE) of the TFTPA device is up to 19.39%, whereas the hysteresis effect is weak, and the PCE is improved by 20.4% compared with the control device which does not have a TFTPA interlayer. Particularly, the moisture stability of the TFTPA device is greatly improved as compared to the control device. Our findings illustrate that the back contact interface engineering is an important and promising approach for inverted planar perovskite solar cells.

3.
J Mater Chem B ; 4(48): 7882-7887, 2016 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-32263778

RESUMO

A series of all-conjugated polythiophene diblock copolymers containing hydrophobic (hexyl) and hydrophilic (triethylene glycol) side chains were synthesized via a nickel-catalyzed quasi-living polymerization. The correlations between block ratios and the self-assembled nanostructures of the block copolymers in thin films and in various solutions were examined. The copolymers dispersed in water via a slow dialysis method produced molecular-level self-assembled core-shell nanospheres with a crystallized hydrophobic core and a hydrophilic amorphous shell, which was proved by TEM images. The size and quantum yield of polymer micelles could be easily tuned via the block ratio of copolymers. The resulting core-shell nanospheres of BP40 composed of 40 mol% P3HT blocks with an average size of 120 nm exhibit high quantum yield (19% in aqueous medium), good photostability and low cytotoxicity. Utilized as a far-red/near-infrared (FR/NIR) cellular probe, BP40 is internalized efficiently by the cells and accumulated in the cytoplasm to give bright fluorescence.

4.
Opt Express ; 23(15): 19442-52, 2015 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-26367603

RESUMO

A new photonic approach of microwave waveform generator based on time-domain synthesis is proposed and experimentally demonstrated, in which two single-drive Mach-Zehnder modulators biased at quadrature point are severed as optical pulse carvers and various microwave waveforms can be generated by carving and overlapping optical field envelopes. The theoretical analysis and simulation are developed. In experiment, a square waveform with 50% duty cycle, triangular waveform with full duty cycle, and sawtooth (or reversed-sawtooth) waveform with 50% duty cycle are generated. Furthermore, a frequency doubling sawtooth (or reversed-sawtooth) waveform with full duty cycle is also obtained.

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