Cold-Trap-Mediated Broad Dynamic Photodetection in Graphene–Organic Hybrid Photonic Barristors

Abstract

One of the most popular approaches to improve the performance of organic photonic devices has been to control the electrically heterogeneous charge-transferring interfaces via chemical modifications. Despite intense research efforts, however, the rapid pace of material evolution through the chemical versatility of the organic compound allows only limited room for the fine-tuning of the interfaces exclusive to specific materials. This limitation leads to an ill-controlled charge recombination behavior that relies solely on the inherent characteristics of each material; thus, the common device architecture cannot harness its full potential. In this work, we demonstrate the use of a graphene−organic hybrid barristor-type phototriode architecture as an alternative platform to realize a linearly and highly photosensitive photodetector operating in a broad dynamic range with rapid temporal responses. With the capability of interfacial energetic modulation, our model system exhibits the dominance of swiftly saturable and slowly responding "cold" traps (T C < 3kT) in charge recombination behaviors, leading to a broad linear dynamic range of 110 dB as well as unconventional illumination-driven increments of both D* and R up to 10 13 Jones and 360 mA/W, respectively, that surpass the best-reported organic photodiodes. Our findings demonstrate that the organic−graphene hybrid photonic barristor architecture can open new avenues to design high-performance photodetectors for various photonic applications in the future.

Monolithic Tandem Multicolor Image Sensor Based on Electrochromic Color‐Radix Demultiplexing

“…The power dependence of the R value (, where a = 1 indicates no recombination and a = 0.5 indicates complete bimolecular recombination) at a ≈ 0.9 indicates that the photocurrent extraction from the device is largely governed by bimolecular recombination rather than by trap‐assisted or geminate recombination. [ 13 ] The temporal and sequential measurement of the photoresponses at different wavelengths and V G values also demonstrates the outstanding color selectivity of the photodetector (Figure S9, Supporting Information).…”

“…This result can be understood in the framework of unsaturated trap‐mediated recombinations dominating the charge dynamics at low light intensities. [ 13 ] We also examined the photoresponse of the monolithic tandem multicolor photodetector. Semi‐logarithmic and linear plots of I D versus V G under 520 nm illumination and 655 nm illumination (optical power: 100 µW) are plotted in Figures 4e and 4f, respectively.…”

“…[ 7,8 ] In particular, electronic technologies for managing optical inputs, such as image sensors, optical communication systems, and optical switching devices, have been rigorously investigated with the aims of harnessing the full potential of their advanced temporal and spatial data processing capabilities and meeting the requirement of digitizing real‐world images. [ 9–15 ] Indeed, the performance of image sensor technology in terms of sensitivity, detectivity, color discrimination, and color accuracy has greatly benefited from the development of sophisticated device‐ and circuit‐level signal detection schemes. [ 16–21 ] However, increasing the level of integration of image sensors to match that of the current semiconductor technology remains a fundamental challenge.…”

“…Furthermore, OSC‐based photodetectors or image sensors, that is, organic photodetectors, have been reported to exhibit superior performance to their inorganic counterparts, for example, more linear dynamic responses and higher specific detectivity, because the latter devices have inherently low noise current density. [ 13,28–30 ] Despite such great potential of vertically integrated multicolor PDs, the number of required terminals and consequently the circuit complexity of these devices remain the same as those of the conventional laterally integrated image sensors, in which three‐color integration necessitates at least six separate terminals that need to be individually connected to the active matrix. In view of this issue, several researchers have developed computational photosensors whose circuit complexity can be greatly reduced through monolithic vertical integration of multilayers or the use of a single tunable broadband absorber.…”

Engineering sensitivity and spectral range of photodetection in van der Waals materials and hybrids

“…Typically, the photodetection mechanism in organic-2D hybrid photodetectors is dominated by traps that usually capture one type of carrier and result in a large internal gain due to photovoltaic, photoconductive or photogating effects [159][160][161]. However, there is still not much clarity about the exact charge transport mechanism occurring in hybrid organic/2D vdW heterostructure system.…”