Monolithic Interface Contact Engineering to Boost Optoelectronic Performances of 2D Semiconductor Photovoltaic Heterojunctions

Abstract

In optoelectronic devices based on two-dimensional (2D) semiconductor heterojunctions, the efficient charge transport of photogenerated carriers across the interface is a critical factor to determine the device performances. Here, we report an unexplored approach to boost the optoelectronic device performances of the WSe2–MoS2 p–n heterojunctions via the monolithic-oxidation-induced doping and resultant modulation of the interface band alignment. In the proposed device, the atomically thin WO x layer, which is directly formed by layer-by-layer oxidation of WSe2, is used as a charge transport layer for promoting hole extraction. The use of the ultrathin oxide layer significantly enhanced the photoresponsivity of the WSe2–MoS2 p–n junction devices, and the power conversion efficiency increased from 0.7 to 5.0%, maintaining the response time. The enhanced characteristics can be understood by the formation of the low Schottky barrier and favorable interface band alignment, as confirmed by band alignment analyses and first-principle calculations. Our work suggests a new route to achieve interface contact engineering in the heterostructures toward realizing high-performance 2D optoelectronics.

Excellent Excitonic Photovoltaic Effect in 2D CsPbBr3/CdS Heterostructures

“…As we can see, the highest FF of 50.4% and PCE of 17.5% are obtained under an irradiation power density of 0.22 and 1.57 mW cm −2 , respectively. The excellent PV performances of the CsPbBr 3 /CdS are superior to the similar dimensional 2D p–n PV devices [ 30–33 ] and comparable to that of perovskite‐based film solar cells. [ 34–36 ] The detailed performance parameters are shown in Table S1, Supporting Information.…”

Synthesis of two‐dimensional transition metal dichalcogenides for electronics and optoelectronics

“…2D‐layered TMDCs and their vdWHs materials have been attracted enormous research interest because of their outstanding response to the light, which promotes the potential applications in next‐generation optoelectronic devices, including photodetectors, 188‐192 photovoltaics, 193 light emitting diodes (LEDs), 194,195 and so on. Herein, we mainly summarize the recent progress of optoelectronic applications in the following three aspects: photodetectors, photovoltaics, and LEDs.…”

“…The Schottky barrier (SB) between Gr and WSe 2 is significantly reduced due to upward band bending when the WOx layer is introduced. F‐H, Reproduced with permission from Reference 193…”

“…Moreover, the simulation results for devices with further‐optimized geometries showed that the metal transfer process gives a hope for fabricating Schottky‐junction TMDCs solar cells with PCE larger than 8% and specific powers greater than 50 kW kg −1 (Figure 15E). Recently, Yang et al 193 reported an unexplored approach to improve the optoelectronic performances of the WSe 2 /MoS 2 heterojunction device (Figure 15F) via the monolithic‐oxidation‐induced doping and resultant modulation of the interface band alignment. By introducing the ultrathin WO x layer, the fabricated device exhibits obvious enhancement in I sc , V oc , FF, and PEC.…”

First-principles Study on Nanoscale Tungsten Oxide: a Review

“…随着人们对节能环保材料的日益关注，能够节 约能源、对太阳能高效利用的智能窗进入人们的视 野，智能窗可动态调节光强、热辐射量及散热量 [77][78] ，满足人们对室内供暖、制冷、隔热的不同需求。 作为性能优越的电致变色材料，氧化钨在智能窗领 域的应用前景广阔，越来越受到人们的关注。 近些年来，为完善和提高氧化钨的电致变色性 能，科研人员采用多种途径对其进行模拟计算。最 初认为立方结构的氧化钨结构简单、对称性好、操 作方便 [79][80][81] ，常以其为基本模型开展第一性原理的 模拟计算工作。但因为模型被过度简化，计算结果 经常与实际数值有较大出入。随后人们开始重视氧 化钨中被忽略的钨氧八面体倾斜畸变和结构畸变， 并在此基础上开展了氧化钨材料对光的吸收、 辐射、 能量转化等研究工作。 秦京运等 [29] [29] Fig. 5 Top view of the supercell of Ti-doped h-WO3 [29] Yang [82]…”