Trapped Photons Induced Ultra-high External Quantum Efficiency and Photoresponsivity with Millisecond Response in Hybrid Graphene/Metal-Organic Framework Broadband Wearable Photodetectors

Metal-Organic frameworks (MOFs) are the promising new class of hybrid materials that has the tremendous attraction in sensing, gas storage, and drug delivery during past two decade due to its unique tunable properties and fascinating architectures. Optoelectronic application of MOF is challenging due to its high porosity and poor electrical conductivity. Combining the superior properties of the MOF along with ultra-high carrier mobility of graphene, we have fabricated and characterize the highly sensitive, broadband, and wearable photodetector on a polydimethylsiloxane substrate. The external quantum efficiency of the hybrid photodetector is found to be > 5×10⁸%, under the excitation of 325 nm laser of intensity ~ 0.5 µWcm^-2, which exceeds all the reported values of similar devices. The porosity of the MOF and ripple structure graphene assist the trapping of photons at the light-harvesting layer. The device photoresponsivity is found to be > 10⁶ AW^-1 with a response time of < 70 ms, which is ~100 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 is demonstrated, which can be stretched up to 100% of its original dimension.