Metal‐organic frameworks (MOFs) have recently emerged as attractive materials for their tunable properties, which have been utilized for diverse applications including sensors, gas storage, and drug delivery. However, the high porosity and poor electrical conductivity of MOFs restrict their optoelectronic applications. Owing to the inherent tunability, a broadband photon absorbing MOF can be designed. Combining the superior properties of the MOFs along with ultrahigh carrier mobility of graphene, for the first time, this study reports a highly sensitive, broadband, and wearable photodetector on a polydimethylsiloxane substrate. The external quantum efficiency of the hybrid photodetector is found to be >5 × 108%, which exceeds all the reported values of similar devices. The porosity of the MOF and ripple structure graphene can assist the trapping of photons at the light‐harvesting layer. The device photoresponsivity is found to be >106 A W−1 with a response time of <150 ms, which is approximately ten times faster than the current standards of the graphene‐organic hybrid photodetectors. In addition, utilizing the excellent flexibility of the graphene layer the wearability of the devices with stretchability up to 100% is demonstrated. The unique discovery of MOF‐based high‐performance photodetectors opens up a new avenue in organic–inorganic hybrid optoelectronics.

Numerous investigations of photon upconversion in lanthanide-doped upconversion nanoparticles (UCNPs) have led to its application in the fields of bioimaging, biodetection, cancer therapy, displays, and energy conversion. Herein, we demonstrate a new approach toward lanthanidedoped UCNPs and a graphene hybrid planar and rippled structure photodetector. The multi-energy sublevels from the 4f n electronic configuration of lanthanides results in longer excited state lifetime for photogenerated charge carriers. This opens up a new regime for ultra-high-sensitivity and broadband photodetection. Under 808 nm infrared light illumination, the planar hybrid photodetector shows a photoresponsivity of 190 AW −1 , which is higher than the currently reported responsivities of the same class of devices. Also, the rippled graphene and UCNPs hybrid photodetector on a poly(dimethylsiloxane) substrate exhibits an excellent stretchability, wearability, and durability with high photoresponsivity. This design makes a significant contribution to the ongoing research in the field of wearable and stretchable optoelectronic devices.

Dual-functional devices that can simultaneously detect light and emit light have a tremendous appeal for multiple applications, including displays, sensors, defense, and high-speed optical communication. Despite the tremendous efforts of scientists, the progress of integration of a phototransistor, where the built-in electric field separates the photogenerated excitons, and a light-emitting diode, where the radiative recombination can be enhanced by band offset, into a single device remains a challenge. Combining the superior properties of perovskite quantum dots (PQDs) and graphene, here we report a light-emissive, ultrasensitive, ultrafast, and broadband vertical phototransistor that can simultaneously act as an efficient photodetector and light emitter within a single device. The estimated value of the external quantum efficiency of the vertical phototransistor is ∼1.2 × 10 10 % with a photoresponsivity of >10 9 A W −1 and a response time of <50 μs, which exceed all the presently reported vertical phototransistor devices. We also demonstrate that the modulation of the Dirac point of graphene efficiently tunes both amplitude and polarity of the photocurrent. The device exhibits a green emission having a quantum efficiency of 5.6%. The moisture-insensitive and environmentally stable, light-emissive, ultrafast, and ultrasensitive broadband phototransistor creates a useful route for dual-functional optoelectronic devices.