Novel Excitonic Solar Cells in Phosphorene–TiO₂ Heterostructures with Extraordinary Charge Separation Efficiency

Abstract

Constructing van der Waals heterostructures is an efficient approach to modulate the electronic structure, to advance the charge separation efficiency, and thus to optimize the optoelectronic property. Here, we theoretically investigated the phosphorene interfaced with TiO2(110) surface (1L-BP/TiO2) with a type-II band alignment, showing enhanced photoactivity. The 1L-BP/TiO2 excitonic solar cell (XSC) based on the 1L-BP/TiO2 exhibits large built-in potential and high power conversion efficiency (PCE), dozens of times higher than conventional solar cells, comparable to MoS2/WS2 XSC. The nonadiabatic molecular dynamics simulation shows the ultrafast electron transfer time of 6.1 fs, and slow electron–hole recombination of 0.58 ps, yielding >98% internal quantum efficiency for charge separation, further guaranteeing the practical PCE. Moreover, doping in phosphorene has a tunability on built-in potential, charge transfer, light absorbance, as well as electron dynamics, which greatly helps to optimize the optoelectronic efficiency of a XSC.

Black Phosphorus: Critical Review and Potential for Water Splitting Photocatalyst

“…At the moment, research for its application in areas such as electronics, optoelectronics and batteries is in progress [4,5,6,8,50,51,52,53,54]. …”

“…On the other hand, its possibility as a water splitting photocatalyst has not been studied much. Recently, several researches adopted black phosphorus as a photocatalyst or photoelectrode [8,9,10]. Zhou et al [8] proposed TiO 2 , black phosphorus heterostructure for the solar cell and Sa et al [9] suggested strain engineering of the black phosphorus for its future application as a photocatalyst.…”

“…Thus, constructing heterostructure with black phosphorus, which absorbs the visible light region, can be an effective solution for drawback of oxide photocatalysts. Zhou et al [8] constructed the heterostructure by depositing monolayer black phosphorus on the TiO 2 substrate (110) surface. Constructed heterostructure shows extraordinary charge separation efficiency, which result in high PCE and enhanced photoactivity.…”

“…Due to its distinct properties compared with other two-dimensional materials, black phosphorus is extensively studied in field effect transistors and other electronic devices [4,5,6,7]. In recent years, according to several researches, it is reported that black phosphorus can also be a promising candidate for solar water splitting [8,9,10]. …”

2D Black Phosphorus: from Preparation to Applications for Electrochemical Energy Storage

“…Table 1 summarizes the structures and properties of monolayer BP and bulk BP in comparison with the more mature and well‐studied graphene. On the basis of intrinsic characteristics, 2D BP has been investigated for use in various applications, including transistor,54, 60, 61, 62 solar cell,63, 64 thermoelectric,65, 66, 67 heterojunction p–n diode,68, 69 sensing,70, 71 photovoltaic devices,72 and photodetectors 73, 74…”