Chemically Bonded N-PDI-P/WO3 Organic-Inorganic Heterojunction with Improved Photoelectrochemical Performance

Cheng Feng,Jiefeng Hai,Zhenhuan Lu,Xihong Mi,Dayong Fan,Dingwen Zhong,Yongping Liu,Ming Li,Weiming Zhang

doi:10.3390/catal10010122

Abstract

The chemical bonding of bandgap adjustable organic semiconductors with inorganic semiconducting materials is effective in constructing a high-performance heterogeneous photoanode. In this study, a new asymmetric perylene diimide derivative molecule (N-PDI-P) was synthesized by connecting tert-butoxycarbonyl on an N-site at one end of a PDI molecule through methylene and connecting naphthalene directly onto the other end. This molecule was bonded onto the WO3 film surface, thereby forming the photoanode of organic-inorganic heterojunction. Under light illumination, the photocurrent density of chemically bonded N-PDI-P/WO3 heterojunction was twofold higher than that of physically adhered heterojunction for photoelectrochemical water oxidation at 0.6 V (vs. Ag/AgCl). Energy band structure and charge transfer dynamic analyses revealed that photogenerated electron carriers on the highest occupied molecular orbital (HOMO) of an N-PDI-P molecule can be transferred to the conduction band of WO3. The charge transfer and separation rates were accelerated considerably after the chemical bond formed at the N-PDI-P/WO3 interface. The proposed method provides a new way for the design and construction of organic-inorganic composite heterojunction.

Highlights

The photoelectrocatalytic decomposition of water is an effective way to transform solar energy into an important clean energy, hydrogen [1,2,3,4]
The mono-side anhydride product was synthesized under the catalytic condition of p-toluene sulfonic acid; thirdly, the mono-side anhydride product was reacted with naphthylamine to obtain the mono-side imide product; the mono-side imide product was anhydrided by p-toluene sulfonic acid and imidized with L-phenylalanine tert-butyl ester to obtain the final product N-perylene diimide diimide derivative derivative (PDI)-P. 1 H NMR (500 MHz, CDCl3 ) δ ppm: 8.74 (d, 2H), 8.62 (d, 2H), 8.57 (q, 4H), 7.43–8.00 (m, 7H), 7.07–7.23 (m, 5H), 6.00, 3.71, 3.53, 1.50 (s, 9H); 13 C
A new N-PDI-P molecule was synthesized in this study

Summary

Introduction

The photoelectrocatalytic decomposition of water is an effective way to transform solar energy into an important clean energy, hydrogen [1,2,3,4]. The half-reaction of water decomposition at anodic oxidation is relatively slow, which is the main barrier of the entire reaction [5]. The development of high-activity photoanode has attracted wide attention. With an energy bandwidth of approximately 2.6 eV, WO3 , which is an important photoanode material, can absorb approximately 12% ultraviolet-visible light (UV-vis) in sunlight. Constructing heterojunction is an effective way of expanding the visible light (vis) absorption range and promoting light-induced charge separation of semiconductors [15,16,17,18,19]

Methods

Results

Conclusion