Photodetectors Research Articles

Numerical modelling of lead-free perovskite photodetector with GO as ETM and Cz-N as HTM

Photodetectors (PD) are optoelectronic devices that can convert optical signal into electrical signals via the photoelectric effect. A model of CsSn0.5Ge0.5I3 based nip perovskite photodetector (PePd) with graphene oxide (GO) as electron transport material (ETM) and carbazole unit with naphthalene (Cz-N) is used as hole transport material (HTM) are established. The device configuration was analysed using solar cell capacitance simulator-1 dimensional (SCAPS-1D). The effects of absorber thickness, defect density of CsSn0.5Ge0.5I3, metal work function and operating temperature on device architecture have been investigated. For the incident light between 800-820 nm, a maximum responsivity and detectivity 0.65 A/W and 3.6×1013 Jones are obtained respectively. This simulation results will assist in the future research on high-performance lead-free perovskite photodetectors.

Ag@WO3 core-shell nanocomposite for wide range photo detection.

This study successfully synthesized high-performance photodetectors based on Ag-WO3 core-shell heterostructures using a simple and economical two-step pulsed laser ablation in water method and has investigated the electrical characteristics of the Ag@WO3 nanocomposite heterojunction. The Hall effect tests indicate that the synthesized Ag@WO3 exhibits n-type conduction with a Hall mobility of 1.25 × 103 cm2V-1S-1. Dark current-voltage properties indicated that the created heterojunctions displayed rectification capabilities, with the highest rectification factor of around 1.71 seen at a 5V bias. A photodetector's responsivity reveals the existence of two response peaks, which are situated in the ultraviolet and visible region. The photodetector demonstrates a rapid response time of less than 100ms. The detectivity values for wavelengths of 350nm and 490nm were 35 × 1013 Jones and 28 × 1013 Jones, respectively. The n-Ag-WO3/n-Si photodetector achieved a maximum EQE of 11.5% in the ultraviolet wavelength when subjected to 3V and illuminated with 350nm (26 mW/cm2) light. The devices demonstrate rapid switching behavior with a rise time of 0.32s and a fall time of 0.33s. The time-dependent light response of a photodetector under illumination at 26 mW/cm2 is seen at a bias of 3V. The light exhibits a rise and decay duration of 15s, while the photocurrent gain is measured at 9µA. The photocurrent of devices exhibited a positive correlation with the incoming light intensity, suggesting that the junction has the potential to function as a photo detector.

Highly-efficient (>70%) and Wide-spectral (400-1700 nm) sub-micron-thick InGaAs photodiodes for future high-resolution image sensors.

This paper demonstrates the novel approach of sub-micron-thick InGaAs broadband photodetectors (PDs) designed for high-resolution imaging from the visible to short-wavelength infrared (SWIR) spectrum. Conventional approaches encounter challenges such as low resolution and crosstalk issues caused by a thick absorption layer (AL). Therefore, we propose a guided-mode resonance (GMR) structure to enhance the quantum efficiency (QE) of the InGaAs PDs in the SWIR region with only sub-micron-thick AL. The TiOx/Au-based GMR structure compensates for the reduced AL thickness, achieving a remarkably high QE (>70%) from 400 to 1700 nm with only a 0.98 μm AL InGaAs PD (defined as 1 μm AL PD). This represents a reduction in thickness by at least 2.5 times compared to previous results while maintaining a high QE. Furthermore, the rapid transit time is highly expected to result in decreased electrical crosstalk. The effectiveness of the GMR structure is evident in its ability to sustain QE even with a reduced AL thickness, simultaneously enhancing the transit time. This breakthrough offers a viable solution for high-resolution and low-noise broadband image sensors.

Self-powered Sb2S3 photodetectors with efficient carrier transport enabled by compact vertical TiO2 nanorods.

Antimony sulfide (Sb2S3) photodetectors (PDs) possess extensive application prospects. Efficient carrier transport of a PD significantly affects the detectivity and response speed. Herein, we propose an all-inorganic self-powered Sb2S3 PD based on vertical TiO2 nanorods (NRs). The spray-coated 15-nm TiO2 thin film as a seed layer ensures the growth of compact vertical TiO2 nanorod arrays by the hydrothermal method. One-dimensional TiO2 nanorods facilitate photocarrier separation and transport to enhance device performance. Ultimately, the Sb2S3 PD achieves a responsivity of 0.29 A/W, a specific detectivity of 3.37 × 1012 Jones, and a response time of 7.8 µs, showing great potential in commercial applications.

Excellent Wavelength Selectivity of p-AlGaN/n-Ga2O3 Solar-Blind UVC PD.

Due to the advantages of ultrawide bandgap, chemical stability, self-powered, and low cost, gallium oxide (Ga2O3) based photodetectors (PDs) are considered as one of the most promising solar-blind ultraviolet PDs, having garnered significant attention in fields such as missile warning and flame arc detection. High selective ratios and excellent responsivity are important to reduce the false alarm rate in solar-blind detection. However, due to the lack of p-type Ga2O3, existing Ga2O3-based PN PDs utilized heterostructures with narrower bandgap p-type semiconductors (e.g., p-GaN, p-SiC, etc.), inducing poor selective ratios with visible light and ultraviolet-A/B (UVA/B). Therefore, a high Al content AlGaN was used in this study to form a p-AlGaN/n-Ga2O3 solar-blind ultraviolet-C (UVC) PD. Since the bandgap of p-AlGaN aligned with the UVC region, the device exhibited exceptionally high selective ratios with R247nm/R360nm = 3.71 × 105 and R247nm/R300nm = 1.47 × 105 at 0 V, which surpassed the reported Ga2O3-based PN PDs. The formation of the type-II heterojunction facilitated the effective separation and transport of photogenerated carriers, resulting in high responsivity (0.36 A/W) under zero bias. Overall, the high selective ratios and high responsivity of the p-AlGaN/n-Ga2O3 PD in this paper provided a reliable pathway for self-powered solar-blind PDs with a low false alarm rate.

Design and Performance of an InAs Quantum Dot Scintillator with Integrated Photodetector

A new scintillation material composed of InAs quantum dots (QDs) hosted within a GaAs matrix was developed, and its performance with different types of radiation is evaluated. A methodology for designing an integrated photodetector (PD) with a low defect density and that is optically matched to the QD’s emission spectrum is introduced, utilizing an engineered epitaxial InAlGaAs metamorphic buffer layer. The photoluminescence (PL) collection efficiency of the integrated PD is examined using two-dimensional scanning laser excitation. The detector response to 5.5 MeV α-particles and 122 keV photons is presented. Yields of 13 electrons/keV for α-particles and 30–60 electrons/keV for photons were observed. The energy resolution of 12% observed with α-particles was mainly limited by noise- and geometry-related optical losses. The radiation hardness of an InAs QDs hosted within GaAs and a wider band gap AlGaAs ternary alloy was studied under a 1 MeV proton implantation up to a 1014 cm−2 dose. The integrated PL responses were compared to evaluate PL quenching due to non-radiative defects. The QDs embedded in the AlGaAs demonstrated improved radiation hardness compared to QDs in the GaAs matrix and in the InGaAs quantum wells.

Foundry fabricated compact slow-light Mach-Zehnder modulator and photodetector for on-chip analog photonic computing

This work presents a scaling pathway of on-chip analog photonic computing using foundry-fabricated silicon electro-optic (EO) slow-light Mach-Zehnder modulators (SL-MZMs) and compact Ge photodetectors (PDs) to construct a computing unit. Two SL-MZMs with phase shifter (PS) lengths of 500 μm and 150 μm are studied in this work. The bit resolution, nonlinearity, clock frequency, and power consumption of the photonic computing link, including an RF amplifier, on-chip SL-MZM, and a PD, are thoroughly investigated. The computing link using the SL-MZM with 500 μm has demonstrated a low normalized mean square error (NMSE) of 0.0305 at 8-bit resolution under 3.2 GHz clock frequency. Under the setting of 6-bit resolution at a clock frequency of 800 MHz, high computing accuracy was achieved with a measured NMSE of 0.0018 using the SL-MZM with 150 μm PS length. Using the Google Speed Commands dataset to run a voice keyword spotting task, we determine that 6-bit resolution operating at 3.2 GHz achieves the optimal power-accuracy trade-off. We show a 20× improvement in energy efficiency and a 3.35× improvement in area efficiency compared to NVIDIA V100 GPU [“Volta: Performance and programmability,” IEEE Micro 38(2), 42 (2018)10.1109/MM.2018.022071134 ]. These results show that our compact SL-MZMs and PDs promise to scale up photonic computing for practical machine-learning applications.

Insight into interfacial dynamics of photogenerated carriers in Cs3Bi2I9/Au heterostructure nanocomposites for high-sensitivity broadband photodetection with negative photoconductivity

The negative photoconductivity (NPC) effect is becoming an increasingly significant factor in the development of next-generation optoelectronics. However, research in the field of NPC-dominated optoelectronics remains in its infancy and frequently encounters challenges related to fabrication complexity, slow photoresponse speed, instability, and a limited spectral response range. Herein, a Cs3Bi2I9/Au heterostructure nanocomposite was prepared via a simple self-assembly process utilizing electrostatic interactions with Au nanoparticles (NPs) and lead-free Cs3Bi2I9 nanoplates. The Cs3Bi2I9/Au nanocomposite-based photodetectors (PDs) demonstrate a broadband photoresponse (405–1550 nm), enhanced rise/fall times (27.2/40.0 µs), and reduced noise density (4.7 × 10−13 A/Hz1/2 at 1 Hz). In contrast to the positive photoconductivity (PPC) effect observed in colloidally synthesized Cs3Bi2I9 nanoplate-based PDs, the NPC can be attributed to the decrease in photocurrent under light illumination during the processes of recombination and trapping of photogenerated carriers induced by the incorporation of Au NPs. These findings are expected to provide valuable insights into achieving high-performance NPC-dominated PDs by regulating the dynamics of photogenerated carriers in perovskite heterostructures.

Device Applications Enabled by Bandgap Engineering Through Quantum Dot Tuning: A Review.

Quantum dots (QDs) are becoming essential materials for future scientific and real-world applications, owing to their interesting and distinct optical and electrical properties compared to their bulk-state counterparts. The ability to tune the bandgap of QDs based on size and composition-a key characteristic-opens up new possibilities for enhancing the performance of various optoelectronic devices. These advances could extend to cutting-edge applications such as ultrawide-band or dual-band photodetectors (PDs), optoelectronic logic gates, neuromorphic devices, and security functions. This paper revisits the recent progress in QD-embedded optoelectronic applications, focusing on bandgap tunability. The current limitations and challenges in advancing and realizing QD-based optoelectronic devices are also discussed.

Femtosecond-laser-induced suprawavelength two-dimensional ZnO microstructures for multi-wavelength photodetector devices.

Herein, we report on two-dimensional (2D) suprawavelength crystalline ZnO microstructures induced by a single ultraviolet (UV) femtosecond laser beam (400 nm, 35 fs, 666 Hz) with significant absorption enhancement. The achieved absorption values of 90-99% and 75-80% in the UV and visible spectral regions, respectively, were approximately 1.16 and 12 times higher than those of the blank ZnO crystal. Furthermore, large-area 2D ZnO microstructures were fabricated to be used as photodetectors (PDs). The experimental results demonstrated that, compared with the blank ZnO, these 2D ZnO microstructures effectively enhanced the PD performance by nearly four times at 375 nm. More importantly, the ZnO microstructure exhibited great response value, ∼7.12 A/W at 532 nm as well as acceptable response at 660 and 808 nm, whereas the blank ZnO crystal showed almost no response. Raman analyses demonstrated that no change occurred after the femtosecond laser induced the microstructure on ZnO. Thus, the enhancement in photoelectric performance can be attributed to the strong absorption of the ZnO microstructure.

Controlled Growth of 2D‐3D Perovskite Lateral Heterostructures for Wavelength‐Tunable Light Communication

AbstractLateral heterostructures based on halide perovskites exhibit great potential in the advancement of next‐generation optoelectronic devices. Among them, mixed dimensional perovskite heterostructures, particularly 2D‐3D ones, offer promising opportunities for semiconductor integration and device miniaturization by combining the advantages of 2D and 3D perovskites. However, the controllable and rapid growth of 2D‐3D halide perovskite lateral heterostructures has not yet been achieved. This study presents an efficient strategy that integrates one‐pot method and space‐confined process to enable liquid‐phase lateral growth of a series of 2D Ruddlesden‐Popper (RP) perovskites on the sides of 3D perovskites. The photodetectors (PDs) based on (BA)2MAn‐1PbnBr3n+1‐MAPbBr3 (n = 1, 2, 3) lateral heterostructures demonstrate outstanding optoelectronic performance, featuring an on/off ratio of up to 1.4 × 104, a high responsivity of 4.4 A W−1 and a detectivity of 3.9 × 1013 Jones at 425 nm, 3 V bias. In addition, by combining the tunable dual‐band photoresponse characteristic with the dual‐beam irradiation modes, a wavelength‐tunable light communication system based on the lateral heterostructure PDs is realized. This work provides a convenient and reliable approach for the direct growth of mixed‐dimensional halide perovskite heterostructures, further demonstrating their potential in high‐performance detecting and dual‐band sensing fields.

SSBI counteraction technology in a single photodetector-based direct detection system receiving an independent dual-single sideband signal

To further meet the large capacity, high spectrum efficiency (SE), reduce the signal-signal beat interference (SSBI) of the independent dual single sideband (ISB) system and the complexity of the receiver, we propose an iterative signal-signal beat interference counteraction (ISSBIC) algorithm to suppress SSBI. The 16-Gbps left sideband and the 16-Gbps right sideband signals in the ISB system are quadrature phase-shift keying (QPSK) modulated. After standard single-mode fiber (SSMF) transmission, the LSB and RSB signals are synthesized to a 16-quadrature amplitude modulation (QAM) signal after conversion through the photodetector (PD) square law. The simulation results show that the ISSBIC with just 2 iterations is superior to Kramers–Kronig (KK) receiver in processing the system error bit. In the meantime, the ISSBIC requires a sampling rate of 20GSa/s, whereas KK requires 40GSa/s. Moreover, the proposed ISSBIC algorithm has a simpler complexity. According to the simulation results, the suggested ISSBIC receiver can lower the ADC requirements and system costs, which opens up a wide range of applications in multiplex and higher SE transmission systems.

Bias‐Induced Gradient Bandgap of Bulk Perovskite Boosting Built‐In Electric Fields for High‐Performance Self‐Powered Photodetectors

AbstractSelf‐powered photodetectors (PDs) have gained significant attention in recent years due to their ability to operate without external power. Strengthening the built‐in electric field (Ebi) of these devices is crucial for efficient carrier separation and transport. However, the disordered energy level arrangement within mixed halide perovskites (MHP) often conflicts with the energy levels constructed by the external interface, weakening the Ebi and thus affecting the performance of self‐powered PDs. In this study, a bias‐induced gradient bandgap of bulk MHP is proposed for high‐performance self‐powered photodetectors. The vector superposition of the bias‐induced gradient bandgap with the interface electric field significantly boosts the Ebi of the device, providing a powerful driving force for the separation and transport of photogenerated carriers. The obtained device exhibits exceptional performance, including an ultra‐fast response time of 1.14/1.75 µs, a large specific detectivity of 7.27 × 1012 cm Hz1/2 W−1, an ultra‐high responsivity of 0.49 A W−1, and an external quantum efficiency of 93.5% at 0 V bias. Furthermore, this strategy is also demonstrated in lateral structure photodetector. This work offers valuable guidance for achieving high‐performance MHP‐based self‐powered PDs through bias‐induced gradient bandgap optimization.

Simultaneous generation of dual 16-QAM-modulated millimeter-wave signals enabled by precoding-based optical I/Q modulation and single photodetector detection

Integration of quadrature-amplitude-modulation (QAM) modulation and millimeter-wave (mm-wave) technology ensures a concise enhancement of transmission capacity and peak data rates in radio-over-fiber (RoF) systems. Nevertheless, with the continuous development of new-generation mobile applications, higher demands on access flexibility have also been formulated. We propose a novel, to the best of our knowledge, dual 16-QAM-modulated mm-wave signal generation scheme for the simultaneous generation and transmission of two independent 16-QAM signals with different carrier frequencies, enhancing the channel capacity, spectrum efficiency, and access flexibility of the RoF systems. In our proposed scheme, the generation of the optical dual 16-QAM-modulated mm-wave signals is implemented by a precoding-based optical in-phase/quadrature (I/Q) modulator operating at optical carrier suppression (OCS) mode, and their detection is implemented by a single photodetector (PD). At the transmitter side, two independent driving QAM vector radio-frequency (RF) signals with precoding, generated via digital signal process (DSP), are fed into two parallel Mach–Zehnder modulators (MZMs) of an I/Q modulator to implement OCS modulation. The I/Q modulator generates optical carriers carrying both information from different QAM signals simultaneously. After square-law detection in a single PD, we generate the desired dual 16-QAM-modulated mm-wave signals with photonic frequency-doubling and recover the original 16-QAM signals without information distortion. Based on our proposed scheme, we experimentally demonstrate the simultaneous generation and transmission of 2-Gbaud dual 16-QAM-modulated mm-wave signals with carrier frequencies of 26 GHz and 40 GHz, respectively. After transmission over 10-km single-mode fiber (SMF) link and 1.2-m wireless link, the dual 16-QAM signals can be successfully separated and demodulated by a common DSP. Bit-error ratios (BERs) of both recovered 16-QAM signals can reach the hard-decision forward-error-correction (HD-FEC) threshold of 3.8×10−3. Compared with the existing schemes, our scheme only requires one-half of the driving frequency to generate dual 16-QAM-modulated mm-wave signals with the same carrier frequency. The result indicates that our proposed scheme can lower bandwidth requirements for optoelectronics devices, along with implementing better spectral efficiency and receiver sensitivity, which is more applicable to the demands for increased system capacity and multi-frequency access flexibility in future systems.

Comprehensive study on the optoelectronic properties of ZnSnP2 compound by DFT and simulation for the application in a photodetector

Abstract This article presents the density function theory (DFT) calculation of ZnSnP2 (ZTP) and its application as a photodetector. A DFT calculation has been performed to determine ZTP's optical and electronic characteristics. The direct bandgap of ZnSnP2 is found to be 1.0 eV which agrees well with the previously reported bandgap (0.95 eV). The total density of states (TDOS) of ZTP is determined to be 1.40 states/eV which is attributed to the 3p orbital of P, with minor impacts from the 3d orbital of Zn and the 5p orbital of Sn to TDOS. The real and imaginary dielectric functions and refractive indices ZTP have been determined to be 16.44 and 17.60, 4.07 and 2.92, respectively. The absorption coefficient and reflectivity of ZTP obtained from this investigation are 2.6×105 cm-1 and 57.5%, respectively. After calculating the electrionic and optical properties, ZTP-based n-CdS/p-ZnSnP2/p+-AlSb photodetector (PD) with CdS and AlSb as the window and back surface field (BSF) layers, respectively, has been computationally analyzed and optimized using solar cell capacitance simulator (SCAPS-1D). In a single heterojunction, the photocurrent, voltage, responsivity, and detectivity values have been obtained at 44.52 mA/cm2, 0.66 V, 0.73 A/W, and 6.81×1013 Jones, respectively. Insertion of a thin AlSb BSF layer improves the photocurrent, voltage, responsivity, and detectivity to 48.75 mA/cm2, 0.78 V, 0.86 A/W, and 8.22×1014 Jones, respectively. The outcomes are highly promising for the fabrication of a high performance ZTP-based PD in the future.

Waveguide-integrated aluminum-MoTe2 Schottky photodetectors for the wavelength band extended to 2 µm.

Transition metal dichalcogenide (TMDC) materials with excellent optoelectronic properties have attracted much attention in the fields of reconfigurable electronic devices, next-generation FETs, and photodetectors (PDs). While normal TMDC PDs have a bandgap-limited absorption edge of ∼1.3 µm, metal-TMDC Schottky PDs based on internal photoemission provide an operation band extension strategy. In this study, we demonstrate that a TMDC PD can even operate at the wavelength band as long as 2.0 µm by judiciously choosing TMDC and metal materials to construct a low barrier height Schottky PD. Specifically, a silicon waveguide-integrated Al-MoTe2 Schottky PD was measured with responsivities of 18 mA/W and 5.5 mA/W at 1.6 µm and 2 µm, respectively. Meanwhile, the dark current is as low as 2 µA. The linear response can be maintained when the input optical power is in the mW scale. A measured 3 dB bandwidth is much larger than 1.75 MHz. These findings offer a promising avenue for expanding the detection range of the TMDC-based PDs with overall good performance in responsivity, bandwidth, sensitivity, and linearity.

High Sensitivity Of Nanocrystalline SnO2-Y2O3 Thin Films Based UV-Detector Prepared Using Chemical Bath Deposition

Nanocrystalline Tin dioxide - Yttrium oxide (NC SnO2-Y2O3) thin film was effectively created by employing the chemical bath deposition approach on SiO2/Si substrates. X-ray diffraction, field emission scanning electron microscopy [FESEM], and energy-dispersive X-ray spectroscopy were used to analyze the structural and the surface morphology of the annealed sample at 500°C for two hours in air. When annealed at 500°C, the SnO2-Y2O3 film crystallized was accomplished with a tetragonal rutile structure. The nanocrystalline SnO2 thin film was effectively employed as a UV photodetector device (UV PDs). A UV photo detector based on nanocrystalline SnO2-Y2O3 film showed 2988% sensitivity when exposed to a 360 nm wavelength (6 mW/cm2) at an applied voltage of 3 V. In contrast, the responsivity value was 3.247 A/W. The rise and full times were determined by calculating to be 0.663 s and 0.436 s, respectively. The excellent performance of the device could be correlated with high surface-to-volume proportions including its elevated crystal performance. Given its outstanding stability and reliability, the nanocrystalline SnO2-Y2O3 thin film sensor is the optimum option for commercially photo-electronic applications.

Tailored Environment-Friendly Reverse Type-I Colloidal Quantum Dots for a Near-Infrared Optical Synapse and Artificial Vision System.

Colloidal quantum dots (QDs) are emerging as potential candidates for constructing near-infrared (NIR) photodetectors (PDs) and artificial optoelectronic synapses due to solution processability and a tunable bandgap. However, most of the current NIR QDs-optoelectronic devices are still fabricated using QDs with incorporated harmful heavy metals of lead (Pb) and mercury (Hg), showing potential health and environment risks. In this work, we tailored eco-friendly reverse type-I ZnSe/InP QDs by copper (Cu) doping and extended the photoresponse from the visible to NIR region. Transient absorption spectroscopy analysis revealed the presence of Cu dopant states in ZnSe/InP:Cu QDs that facilitated the extraction of photogenerated charge carriers, leading to an enhanced photodetection performance. Specifically, under 400 nm illumination, the Cu-doped ZnSe/InP QDs-based PDs presented a broadband photodetection ranging from ultraviolet (UV) to NIR, with a responsivity of 70.5 A W-1 and detectivity of 2.8 × 1011 Jones, surpassing those of the undoped ZnSe/InP QDs-based PDs (49.4 A W-1 and 1.9 × 1011 Jones, respectively). More importantly, the ZnSe/InP:Cu QDs-PDs demonstrated various synapse-like characteristics of short-term plasticity (STP), long-term plasticity (LTP), and learning-forging-relearning under NIR light illumination, which were further used to construct PD array devices for simulating the artificial visual system that is available in prospective optical neuromorphic applications.

A fast and stable calibration method for VLP system without any geometric measurement

Abstract. Visible light positioning (VLP) is one of the most promising technologies for providing high-precision, low-cost indoor positioning and navigation services. However, the traditional calibration methods of VLP are complex and unfriendly to users, which hinders the large-scale commercial deployment of VLP systems. In this letter, a fast and stable calibration method for Lambert model in the received signal strength (RSS)-based VLP system is proposed, which dispenses with geometric measurement and greatly simplifies the calibration procedures. The proposed method calibrates the Lambert model through two steps, firstly using a ratio method to calibrate the Lambert order, and then estimating the constant term. The actual processes only require moving a robot equipped with a photo-detector (PD) along a rectangular trajectory once, and then the program will automatically estimate the required parameters by analyzing the RSS during this period. Experimental results show a good stability of the calibrated parameters, as well as a excellent distance measuring accuracy within 12 cm. And the entire processes, including signal collection and processing, only take a total of no more than four minutes.

A strategy for achieving high-performance single layer polymer photodetectors through dark current reduction using PMMA additives

Suppressing dark current density is crucial for optimizing the performance of organic photodetectors (PDs), particularly in terms of detectivity (D∗) and linear dynamic range (LDR). Organic PDs often utilize the bulk heterojunction structure of organic solar cells to significantly increase photocurrent. However, unlike solar cells, which are unaffected by dark current, photodetectors' performance is substantially limited by it. The interconnected network of bulk heterojunctions leads to a noticeable increase in dark current, thus degrading device performance. Typically, reducing dark current involves adding a modification layer or using multilayer planar heterojunctions, which effectively reduce dark current but often delay response speed and complicate manufacturing. This study presents an alternative approach by incorporating a small concentration of PMMA into single-layer polymer photodetectors, significantly reducing dark current without affecting photocurrent. For this single-layer polymer PD, an ultra-low dark current density of 1.25 × 10−8 A/cm2, a high Dsh∗ of 2.74 × 1012 Jones, an LDR of 120.5 dB, and a fast response time with 1.6 μs were achieved. The capacitance-voltage (C-V), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), and atomic force microscopy (AFM) measurements revealed that the PMMA additive reduces internal defects, increases bulk resistance, optimizes phase separation, and enhances carrier transport efficiency. The improved device performances are attributed to a more efficient vertical arrangement of the donor-acceptor interface and carrier channels, thus reducing carrier recombination loss. These findings offer a new direction for fabricating high-performance single-layer photodetectors.