Silicon‐based electronic devices, especially graphene/Si photodetectors (Gr/Si PDs), have triggered tremendous attention due to their simple structure and flexible integration of the Schottky junction. However, due to the relatively poor light–matter interaction and mobility of silicon, these Gr/Si PDs typically suffer an inevitable compromise between photoresponsivity and response speed. Herein, a novel strategy for coupling 2D In2S3 with Gr/Si PDs is demonstrated. The introduction of the double‐heterojunction design not only strengthens the light absorption of graphene/Si but also combines the advantages of the photogating effect and photovoltaic effect, which suppresses the dark current, accelerates the separation of photogenerated carriers, and brings photoconductive gain. As a result, In2S3/graphene/Si devices present an ultrahigh photoresponsivity of 4.53 × 104 A W−1 and fast response speed less than 40 µs, simultaneously. These parameters are an order of magnitude higher than pristine Gr/Si PDs and among the best values compared with reported 2D materials/Si heterojunction PDs. Furthermore, the In2S3/graphene/Si PD expresses outstanding long‐term stability, with negligible performance degradation even after 1 month in air or 1000 cycles of operation. These findings highlight a simple and novel strategy for constructing high‐sensitivity and ultrafast Gr/Si PDs for further optoelectronic applications.

Alloy engineering and heterostructures designing are two efficient methods to improve the photosensitivity of two-dimensional (2D) material-based photodetectors. Herein, we report the first-principle calculation about the band structure of SnS1–x Se x (0 ≤ x ≤ 1) and synthesize these alloy nanosheets. Systematic measurements indicate that SnS0.25Se0.75 exhibits the highest hole mobility (0.77 cm2·V–1·s–1) and a moderate photoresponsivity (4.44 × 102 A·W–1) with fast response speed (32.1/57.5 ms) under 635 nm irradiation. Furthermore, to reduce the dark current and strengthen the light absorption, a self-driven SnS0.25Se0.75/n-Si device has been fabricated. The device achieved a preeminent photo-responsivity of 377 mA·W–1, a detectivity of ∼1011 Jones and I light/I dark ratio of ∼4.5 × 102. In addition, the corresponding rising/decay times are as short as 4.7/3.9 ms. Moreover, a broadband sensitivity from 635 to 1200 nm is obtained and the related photoswitching curves are stable and reproducibility. Noticeably, the above parameters are comparable or superior to the most of reported group IVA layered materials-based self-driven photodetectors. Last, the synergistic effects between the SnS0.25Se0.75 nanosheets and the n-Si have been discussed by the band alignment. These brilliant results will pave a new pathway for the development of next generation 2D alloy-based photoelectronic devices.

A photodetector based on 2D non‐layered materials can easily utilize the photogating effect to achieve considerable photogain, but at the cost of response speed. Here, a rationally designed tunneling heterojunction fabricated by vertical stacking of non‐layered In2S3 and Te flakes is studied systematically. The Te/In2S3 heterojunctions possess type‐II band alignment and can transfer to type‐I or type‐III depending on the electric field applied, allowing for tunable tunneling of the photoinduced carriers. The Te/In2S3 tunneling heterojunction exhibits a reverse rectification ratio exceeding 104, an ultralow forward current of 10−12 A, and a current on/off ratio over 105. A photodetector based on the heterojunctions shows an ultrahigh photoresponsivity of 146 A W−1 in the visible range. Furthermore, the devices exhibit a response time of 5 ms, which is two and four orders of magnitude faster than that of its constituent In2S3 and Te. The simultaneously improved photocurrent and response speed are attributed to the direct tunneling of the photoinduced carriers, as well as a combined mechanism of photoconductive and photogating effects. In addition, the photodetector exhibits a clear photovoltaic effect, which can work in a self‐powered mode.

For the first time, hybrid white organic light-emitting diodes (WOLEDs) have been developed via the manipulation of exciplex and electroplex emission. Unlike previous hybrid WOLEDs, this novel kind of hybrid WOLED is exciplex/electroplex based hybrid WOLEDs. First, an exciplex/electroplex system is explored, exhibiting the best performance among WOLEDs with emissions generated from exciplex/electroplex systems. Then, with doping-free technology, the single-molecular-emitter WOLED exhibits maximum total external quantum efficiency (EQE) and power efficiency (PE) of 16.8% and 56.4 lm W −1 , respectively, the highest among doping-free hybrid WOLEDs. Besides, PE at 1000 cd m −2 (40.0 lm W −1 ) is higher/efficiency roll-off is lower than some best doping hybrid WOLEDs. The two-molecular-emitter WOLED exhibits (i) a CRI of 92.1, the highest among doping-free WOLEDs (DF-WOLEDs); (ii) a correlated color temperature of 2319 K, the lowest among DF-WOLEDs; and (iii) 2-fold higher efficiency (28.2 lm W −1 ) than the best DF-WOLEDs with ultrahigh color rendering index (CRI > 90). Moreover, the exciplex/electroplex system can be demonstrated to doping hybrid WOLEDs, achieving the EQE and PE of 20.0% and 52.7 lm W −1 at 1000 cd m −2 , respectively, comparable to the best hybrid WOLEDs. Such findings may (i) be the first report that the performance of doping-free hybrid WOLEDs is comparable to that of doping hybrid WOLEDs, (ii) open a new opportunity that a family of materials generating exciplex/electroplex emissions are promising for hybrid WOLEDs, (iii) unlock an alternative concept to develop hybrid WOLEDs, regardless of doping-free or doping structures.

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