Electroluminescence Intensity Research Articles

Temperature-dependent photoluminescent behavior of millimeter-scale Cs4PbBr6/CsPbBr3 bulk crystals and their application to white light-emitting diodes

The zero-dimensional perovskite composite Cs4PbBr6/CsPbBr3 has attracted significant attention for its remarkable photoluminescence (PL), which remains highly effective even in solid state. This work presents a detailed analysis of the steady-state and time-resolved PL (TRPL) behavior of millimeter-scale Cs4PbBr6/CsPbBr3 crystals over a temperature range of 80 to 360 K, which covers exciton binding energy, phonon energy, and PL peak energy shifting with increasing temperature. According to the results, Cs4PbBr6/CsPbBr3 exhibits high exciton binding energy and phonon energy, with calculated values of 358.7 and 94.8 meV, respectively. Specifically, when the temperature is below ∼235 K, thermal expansion dominates to influence the TRPL and peak energy, whereas electron-phonon interaction becomes the dominant factor as temperature rises from 235 to 325 K. It is found that Cs4PbBr6/CsPbBr3 has a PL behavior similar to CsPbBr3, and characterization and TRPL results demonstrate that nanometer-scale CsPbBr3 crystals embed in the Cs4PbBr6 bulk matrix. Meanwhile, a white light-emitting diode (WLED) device based on Cs4PbBr6/CsPbBr3 with luminous efficiency of 64.56 lm/W is fabricated, and its color coordinate is measured as (0.34, 0.31) under 20 mA, which is in close proximity to the standard white color coordinate. Moreover, the color gamut of the device is measured as 128.66% of the National Television Systems Committee (NTSC). The WLED electroluminescence (EL) spectra show high Correlated Color Temperature (CCT) stability for the working current varying from 5 to 100 mA, and after continuous operation for 12 h, the EL intensity decreases and stabilizes at ∼70% of the initial EL intensity. These findings suggest that Cs4PbBr6/CsPbBr3 crystals are a promising candidate for WLEDs.

Improve characteristics of GaN-based green mini-LEDs with double dielectric sidewall passivation

The technique of double dielectric sidewall passivation could improve the electroluminescence characteristics of green mini-LED, including the leakage current, electroluminescence intensity and external quantum efficiency (EQE). According to the analysis of EQE with ABC + f(n) model, both the increment of size and the sidewall passivation could reduce the fraction of SRH recombination. Then, the results of time-resolved photoluminescence measurement indicated that the carrier lifetime of mini-LEDs with higher surface-volume ratio and sidewall passivation would be reduced. Moreover, the communication performances such as modulation bandwidth and frequency response of green mini-LEDs could also be improved by adopting double dielectric sidewall passivation, and the smaller sized green mini-LEDs could achieve higher modulation bandwidth and frequency response.

Piezo-phototronic enhanced dual-wavelength InGaN/GaN multiple quantum wells Micro-LED arrays

As a promising technology for next-generation displays due to their high brightness and low power consumption, InGaN-based micro light-emitting diodes (Micro-LEDs) have attracted great attention in recent years. In this work, we detailedly investigate the carrier recombination and transportation process in dual-wavelength InGaN/GaN multiple quantum wells (MQWs) Micro-LED arrays under piezo-phototronic effects using electroluminescence (EL) and time-resolution photoluminescence measurements. With the increase of external strain, the violet EL intensity of dual-wavelength Micro-LED arrays first increases obtaining a maximum enhancement of ∼12% and then decreases, whereas blue EL emission almost maintains constant. Additionally, as the size of Micro-LED decreases, the enhancement obtained via piezo-phototronic effect will reduce, which is attributed to their inherently weaker piezoelectric polarization effect. Combining with dynamic analysis of carriers in the blue quantum well (QW), it is concluded that strain-induced interface polarized charges promote the wave function overlap of electron–hole pair, but reduce the injection of hole carriers in blue QW. Superposition of the above two factors enables the blue EL intensity stable under piezoelectric coupling. These results present a promising potential of piezo-phototronic effects to improve the Micro-LEDs devices.

Investigating the Thermo-Optic Properties of BCZT-Based Temperature Sensors.

Photoluminescent (PL) layers and electroluminescent (EL) systems have gained significant attention for their applications in constructing flat panels, screen monitors, and lighting systems. In this study, we present a groundbreaking approach to fabricating temperature sensors using barium-calcium zirconium titanate (BCZT) with thermo-optic properties, leading to the development of opto-thermal sensors for electric vehicle battery packs. We prepared zinc sulfide (ZnS) fluorescent films on BCZT ceramics, specifically two optimal compositions, BCZT0.85 (Ba0.85Ca0.15Zr0.1Ti0.9O3) and BCZT0.9 (Ba0.9Ca0.1Zr0.1Ti0.9O3), via the solid-state reaction method for the dielectric layer. The BCZT powders were calcined at varying temperatures (1200 and 1250 °C) and dwell times (2 and 4 h). The resulting phase formation and microstructure characteristics were analyzed using X-ray diffraction and scanning electron microscopy, respectively. Our investigation aimed to establish a correlation between the dielectric behavior and optical properties to determine the optimal composition and conditions for utilizing BCZT as thermal detectors in electric vehicle battery packs. All BCZT powders exhibited a tetragonal phase, as confirmed by JCPDS No. 01-079-2265. We observed an increase in the dielectric constant with higher calcining temperatures or longer dwell times. Remarkably, BCZT0.85 ceramic sintered at 1250 °C for 4 h displayed the highest dielectric constant of 15,342, establishing this condition as optimal for preparing the dielectric film with a maximum dielectric constant of 42. Furthermore, we investigated the temperature-dependent electroluminescence intensity of the samples, revealing a significant enhancement with increasing temperature, reaching its peak at 80 °C. Additionally, we observed a positive correlation between electroluminescence intensity and dielectric constant, indicating the potential for improved opto-thermal sensors. The findings from this study offer promising opportunities for the development of advanced opto-thermal sensors with potential applications in electric vehicle battery packs. Our work contributes to the expanding field of photoluminescent and electroluminescent systems by providing novel insights into the design and optimization of efficient and reliable sensors for thermal monitoring in electric vehicle technologies.

Plasmon-enhanced deep ultraviolet Micro-LED arrays for solar-blind communications.

Localized surface plasmon resonance (LSPR)-enhanced deep ultraviolet (DUV) Micro-light emitting diodes (Micro-LEDs) using Al nanotriangle arrays (NTAs) are reported for improving the -3 dB modulation bandwidth. Through self-assembled nanospheres, the high-density Al NTAs arrays are transferred into the designated p-AlGaN region of the Micro-LEDs, realizing the effect of LSPR coupling. A 2.5-fold enhancement in photoluminescence (PL) intensity is demonstrated. Combined with the PL intensity ratio at 300 K and 10 K, internal quantum efficiency (IQE) may be increased about 15-20% by the plasmonic effect and the carrier lifetime decreases from 1.15 ns to 0.82 ns, suggesting that LSPR accelerates the spontaneous emission rate. Resulting from the improvement of the IQE, the electroluminescence intensity of Micro-LED arrays with LSPR is obviously increased. Meanwhile, the -3 dB bandwidth of 6 × 6 Micro-LED arrays is increased from 180 MHz to 300 MHz at a current density of 200 A/cm2. A potential way is proposed to further increase both the IQE and the modulation bandwidth of DUV Micro-LEDs.

First Dual Red–Near-Infrared Emissive Solution-Processed Organic Light-Emitting Diode Based on Europium–Ytterbium Mixed-Ligand Complexes for Pulse Oximetry

For oximetry applications, the first dual red–near-infrared (NIR) emissive organic light-emitting diode (OLED) based on mixed-ligand complexes EuxYb1–x(dbm)3BPhen (x = 0; 0.01; 0.02; 0.05; 0.1; 1) is obtained. The photoluminescence quantum yields of the ytterbium and europium in the obtained complexes reach 0.9 and 31%, respectively, which are rather high values for the complexes of these ions. Dual visible–NIR emissive compounds EuxYb1–x(dbm)3BPhen are tested in OLEDs, and Eu0.05Yb0.95(dbm)3BPhen demonstrates the most intense electroluminescence both in visible (270 cd/m2) and NIR range (19 μW/cm2). The Eu0.05Yb0.95(dbm)3BPhen-based OLED is successfully used to produce the first lanthanide OLED-based pulsimeter prototype.

Dimension dependence of current injection path in GaInN/GaN multi-quantum-shell (MQS) nanowire-based light-emitting diode arrays

Abstract To light emitting diodes (LEDs), solving the common non-uniform current injection and efficiency degradation issues in (0001) plane micro-LED is essential. Herein, we investigated the light emission characteristics of various mesa sizes and different p-electrode areas toward the realization of coaxial GaInN/GaN multi-quantum-shell (MQS) nanowires (NWs)-based micro-LEDs. As the mesa area was reduced, the current leakage decreases, and further reduction of the area showed a possibility of realizing micro-LED with less current leakage. The large leakage path is mainly associated with the defective MQS structure on the (0001) plane area of each NW. Therefore, more NWs involved in an LED chip will induce higher reverse leakage. The current density-light output density characteristics showed considerably increased electroluminescence (EL) intensity as the mesa area decreased, owing to the promoted current injection into the efficient NW sidewalls under high current density. The samples with a mesa area of 50 × 50 µm2 showed 1.68 times higher light output density than an area of 100 × 100 µm2 under a current density of 1000 A/cm2. In particular, the emission from (1-101) and (10-10) planes did not exhibit an apparent peak shift caused by the quantum-confined Stark effect. Furthermore, by enlarging the p-electrode area, current can be uniformly injected into the entire chip with a trade-off of effective injection to the sidewall of each NW. High performance of the MQS NW-based micro-LED can be expected because of the mitigated efficiency degradation with a reducing mesa area and an optimal dimension of p-electrode.

Enhanced light emission of germanium light-emitting-diode on 150 mm germanium-on-insulator (GOI).

Germanium-on-insulator (GOI) has emerged as a novel platform for Ge-based electronic and photonic applications. Discrete photonic devices, such as waveguides, photodetectors, modulators, and optical pumping lasers, have been successfully demonstrated on this platform. However, there is almost no report on the electrically injected Ge light source on the GOI platform. In this study, we present the first fabrication of vertical Ge p-i-n light-emitting diodes (LEDs) on a 150 mm GOI substrate. The high-quality Ge LED on a 150-mm diameter GOI substrate was fabricated via direct wafer bonding followed by ion implantations. As a tensile strain of 0.19% has been introduced during the GOI fabrication process resulting from the thermal mismatch, the LED devices exhibit a dominant direct bandgap transition peak near 0.785 eV (∼1580 nm) at room temperature. In sharp contrast to conventional III-V LEDs, we found that the electroluminescence (EL)/photoluminescence (PL) spectra show enhanced intensities as the temperature is raised from 300 to 450 K as a consequence of the higher occupation of the direct bandgap. The maximum enhancement in EL intensity is a factor of 140% near 1635 nm due to the improved optical confinement offered by the bottom insulator layer. This work potentially broadens the GOI's functional variety for applications in near-infrared sensing, electronics, and photonics.

Enhancement of luminous efficacy of polymer light‐emitting diodes with silver‐nanoparticles by oxygen‐plasma treatment

Silver-nanoparticles deposited on indium tin oxide (AgNPs/ITO) with different O2 -plasma treatment times are used as the anode window substrate for polymer light-emitting diodes (PLED). When AgNPs/ITO with an O2 -plasma treatment time of 10 min is used for PLED, a maximum current efficiency of 3.33 cd/A is realized, which is notably higher than that of a reference PLED (1.00 cd/A). Compared to those of the reference PLED, the mean current efficiency and electroluminescence intensity of the optimal PLED are enhanced by 3.24 times and 480%, respectively. O2 -plasma treatment is an easy method for optimizing the localized surface plasmon resonance effect of metal nanoparticles, exhibiting advantages of scalable mass production and high suitability for applications in related optoelectronic components.

Modelling Electroluminescence Emission in Polymeric Material Using Dimensional Analysis Method

The Electroluminescence (EL) technique has garnered significant interest over time for its reliable outcomes that enrich our understanding of the onset of electrical degradation in polymeric material. There is growing interest in combining both the EL technique and space charge measurement methods to obtain a more profound knowledge of the degradation and ageing of insulation. The generation of charge carriers in polymeric materials is widely acknowledged to be a crucial aspect of EL, involving injection, de-trapping, and field dissociation processes. This research investigates the variables that influence how EL emissions behave, including applied voltage or electric field, applied electrical frequency, ageing of material, and selection of materials and gases employed. It was found that these factors can be helpful in predicting the process of electrical ageing in insulation to avoid any catastrophes that may occur. A mathematical approach relating these factors and the intensity of EL is proposed through the aid of Dimensional Analysis method. A close relationship is obtained that suggests this mathematical approach can be utilised as a tool to predict electrical ageing of insulation material.

Visualizing electroluminescence process in light-emitting electrochemical cells

Electroluminescence occurs via recombination reactions between electrons and holes, but these processes have not been directly evaluated. Here, we explore the operation dynamics of ionic liquid-based light-emitting electrochemical cells (LECs) with stable electroluminescence by multi-timescale spectroscopic measurements synchronized with the device operation. Bias-modulation spectroscopy, measuring spectral responses to modulated biases, reveals the bias-dependent behavior of p-doped layers varying from growth to saturation and to recession. The operation dynamics of the LEC is directly visualized by time-resolved bias-modulation spectra, revealing the following findings. Electron injection occurs more slowly than hole injection, causing delay of electroluminescence with respect to the p-doping. N-doping proceeds as the well-grown p-doped layer recedes, which occur while the electroluminescence intensity remains constant. With the growth of n-doped layer, hole injection is reduced due to charge balance, leading to hole-accumulation on the anode, after which LEC operation reaches equilibrium. These spectroscopic techniques are widely applicable to explore the dynamics of electroluminescence-devices.

Effect of bulky side groups on photophysical properties and electroluminescent performance of oligo(styryl)benzenes

The rational design of electroluminescent compounds has been recognized as a promising strategy to maximize the efficiency of electronic devices. In this work, we analyze the impact of the substitution of n-alkyl and n-alkoxy side chains by bulkier side groups (tert-butyl and tert-butoxy) on the photophysics of the two model fluorophores 1,3,5-tris(styryl)benzene and 1,2,4,5-tetra(styryl)benzene. We found that the bulky side groups have a significant contribution to the vibrational normal modes associated with the non-radiative deactivation. The aggregation-induced enhanced emission phenomenon observed in some cases was attributed to the blocking of the trans→cis photoisomerization and the restriction of intramolecular vibrations. In the solid state, the bulky side groups have demonstrated to play a determining role in the supramolecular structure and photophysical properties, particularly in the case of the tetra(styryl)benzenes. In light-emitting devices, we found that the incorporation of the bulky side groups in oligo(styryl)benzenes could reduce the electromer formation and improve the device performance. The tetra(styryl)benzenes, and particularly the tert-butyl derivative, showed better device performance, with lower turn-on voltage, higher current density and electroluminescent intensity.

Randomly Disassembled Nanostructure for Wide Angle Light Extraction of Top-Emitting Quantum Dot Light-Emitting Diodes.

The quantum dot light-emitting diode (QLED) represents one of the strongest display technologies and has unique advantages like a shallow emission spectrum and superior performance based on the cumulative studies of state-of-the-art quantum dot (QD) synthesis and interfacial engineering. However, research on managing the device's light extraction has been lacking compared to the conventional LED field. Moreover, relevant studies on top-emitting QLEDs (TE-QLEDs) have been severely lacking compared to bottom-emitting QLEDs (BE-QLEDs). This paper demonstrates a novel light extraction structure called the randomly disassembled nanostructure (RaDiNa). The RaDiNa is formed by detaching polydimethylsiloxane (PDMS) film from a ZnO nanorod (ZnO NR) layer and laying it on top of the TE-QLED. The RaDiNa-attached TE-QLED shows significantly widened angular-dependent electroluminescence (EL) intensities over the pristine TE-QLED, confirming the effective light extraction capability of the RaDiNa layer. Consequently, the optimized RaDiNa-attached TE-QLED achieves enhanced external quantum efficiency (EQE) over the reference device by 60%. For systematic analyses, current-voltage-luminance (J-V-L) characteristics are investigated using scanning electron microscopy(SEM) and optical simulation based on COMSOL Multiphysics. It is believed that this study's results provide essential information for the commercialization of TE-QLEDs.

N-AlGaN Free Deep-Ultraviolet Light-Emitting Diode with Transverse Electron Injection

For the first time, the n-AlGaN free deep-ultraviolet light-emitting diode (DUV-LED) with transverse electron injection by selective area regrowth (SAG) n+-GaN is demonstrated. The multiple quantum wells (MQWs) and upper layers of the transverse structure LEDs that deposited directly on the AlN template exhibit lower threading dislocation density and better surface morphology compared to conventional structure LEDs with thick n-AlGaN layer. The internal quantum efficiency of the transverse structure LED estimated by temperature-dependent photoluminescence is 95%, which is almost twice higher than that of the conventional structure LED (48%). The electroluminescence intensity of transverse structure LEDs is more than twice that of the conventional structure LEDs. Furthermore, the high crystal quality of MQWs enables transverse structure LEDs to emit shorter peak wavelengths (251–254 nm) and narrower full width at half maximums (10.1–10.7 nm). This study demonstrates that by adopting SAG n+-GaN as an electron injection layer, the n-AlGaN free transverse structure LEDs can be realized, enabling a substantial improvement in DUV-LEDs that are generally based on poor crystal quality n-AlGaN.

Monolithic Multicolor Emissions of InGaN-Based Hybrid Light-Emitting Diodes Using CsPbBr3 Green Quantum Dots.

To address the increasing demand for multicolor light-emitting diodes (LEDs), a monolithic multicolor LED with a simple process and high reliability is desirable. In this study, organic-inorganic hybrid LEDs with violet and green wavelengths were fabricated by depositing CsPbBr3 perovskite green quantum dots (QDs) as the light-converting material on InGaN-based violet LEDs. As the injection current was increased, the total electroluminescence (EL) intensities of the hybrid LEDs increased, whereas the light-converted green emission efficiency of the CsPbBr3 QDs decreased. The maximum green-to-violet EL spectral intensity ratio of the hybrid LEDs with CsPbBr3 QDs was achieved with the injection current of <10 mA. Moreover, the EL spectral ratio of the green-to-violet emission decreased at an injection current of 100 mA. The light-conversion intensity of the CsPbBr3 QDs decreased linearly as the junction temperature of the hybrid LEDs was increased with increasing injection current, similar to the temperature-dependent photoluminescence degradation of CsPbBr3 QDs. In addition, the junction temperature of the hybrid LED was minimized by pulse injection to suppress the thermal degradation of QDs and increase the light conversion efficiency to green emission. Therefore, the overall emission spectrum color coordinates of the hybrid LEDs exhibited a red shift from violet to blue in the low-current region and a blue shift toward violet as the green emission of the QDs was decreased above 10 mA.

High-frequency pulsed-electroluminescence from light-emitting diodes based on quasi-2D perovskites (rubidium-doped CsPbBr3)

We report high-frequency pulsed-electroluminescence generation from light-emitting diodes (LEDs) based on quasi-2D perovskites under AC voltages. The quasi-2D form of CsPbBr3 was obtained upon the inclusion of a larger-sized organic cation, namely phenylethylammonium (PEA); the defects in the perovskite were passivated through rubidium-incorporation. The conversion of the perovskite to a lower-dimensional form, along with defect-passivation, has led to the enhancement of PL emission and thereby yielded increased electroluminescence (EL) intensity from the LEDs based on the perovskites. While the devices under a DC voltage have emitted EL only under a forward-bias section, the LEDs operated with AC voltages have resulted in pulsed-light and EL-emissions under reverse-biased half-cycles as well. In this work, we have recorded the dynamic response of the pulsed-light generated from LEDs under AC voltages and varied its frequency to correlate the effect of defect-passivation (through rubidium-doping) with the frequency–response of pulsed EL-emission.

Carrier transport model of non-carrier-injection light-emitting diode

Non-carrier-injection light-emitting diodes (NCI-LEDs) are expected to be widely used in the next-generation micro-display technologies, including Micro-LEDs and nano-pixel light-emitting displays due to their simple device structures. However, because there is no external charge carrier injection, the internal carrier transport behavior of the NCI-LED cannot be described by using the traditional PN junction and LED theory. Therefore, establishing a carrier-transport model for the NCI-LED is of great significance in understanding its working mechanism and improving device performance. In this work, carrier transport mathematical model of the NCI-LED is established and the mechanical behavior of charge-carrier transport is analyzed quantitatively. Based on the mathematical model, the working mechanism of the NCI-LED is explained, the carrier transport characteristics of the device are obtained. Additionally, the key features, including the length of the induced charge region, the forward biased voltage across the internal PN junction, and the reverse biased voltage across the internal PN junction are studied. Their relationships with the applied frequency of the applied driving voltage are revealed. It is found that both the forward bias and reverse bias of the internal PN junction increase with the driving frequency. When the driving frequency reaches a certain value, the forward bias and the reverse bias of the PN junction will be maintained at a maximum value. Moreover, the length of the induced charge region decreases with the increase of the driving frequency, and when the frequency reaches a certain value, the induced charge region will always be in the state of exhaustion. According to the mathematical model, suggestions for the device optimization design are provided below. 1) Reducing the doping concentration of the induced charge region can effectively increase the voltage drop across the internal LED; 2) employing the tunneling effect occurring in the reverse-biased PN junction can effectively improve the electroluminescence intensity; 3) using the square-wave driving voltage can obtain a larger voltage drop across the internal LED and increase the electroluminescence intensity. This work on the carrier transport model is expected to e present a clear physical figure for understanding the working mechanism of NCI-LED, and to provide a theoretical guidance for optimizing the device structure.

Температурная зависимость дислокационной электролюминесценции в кремниевых светодиодах с кислородными преципитатами

Electroluminescence has been studied in silicon light-emitting diodes containing oxygen precipitates at temperatures of 40-300 K. Oxygen ion implantation and multistage anneals are used for fabrication of the diodes. Over all temperature range, spectra are well approximated by one Lorentz and four Gaussian curves. Lines of dislocation-related luminescence D1-D4 (the D1 line is described by Lorentz curve) and oxygen precipitates (OPs) are present in the spectra. At temperature variation, peak positions of the D1, OP and D2 lines coincide with temperature dependence of the forbidden gap width reduced by values of 356, 330 and 303 meV respectively. Build and quenching areas are observed on temperature dependences of the electroluminescence intensities of the D1, OP and D2 lines, the activation energies of the processes are determined, and reasons of their appearance are discussed.

AC-driven multicolor electroluminescence from a hybrid WSe2 monolayer/AlGaInP quantum well light-emitting device.

Light-emitting diodes (LEDs) are used widely, but when operated at a low-voltage direct current (DC), they consume unnecessary power because a converter must be used to convert it to an alternating current (AC). DC flow across devices also causes charge accumulation at a high current density, leading to lowered LED reliability. In contrast, gallium-nitride-based LEDs can be operated without an AC-DC converter being required, potentially leading to greater energy efficiency and reliability. In this study, we developed a multicolor AC-driven light-emitting device by integrating a WSe2 monolayer and AlGaInP-GaInP multiple quantum well (MQW) structures. The CVD-grown WSe2 monolayer was placed on the top of an AlGaInP-based light-emitting diode (LED) wafer to create a two-dimensional/three-dimensional heterostructure. The interfaces of these hybrid devices are characterized and verified through transmission electron microscopy and energy-dispersive X-ray spectroscopy techniques. More than 20% energy conversion from the AlGaInP MQWs to the WSe2 monolayer was observed to boost the WSe2 monolayer emissions. The voltage dependence of the electroluminescence intensity was characterized. Electroluminescence intensity-voltage characteristic curves indicated that thermionic emission was the mechanism underlying carrier injection across the potential barrier at the Ag-WSe2 monolayer interface at low voltage, whereas Fowler-Nordheim emission was the mechanism at voltages higher than approximately 8.0 V. These multi-color hybrid light-emitting devices both expand the wavelength range of 2-D TMDC-based light emitters and support their implementation in applications such as chip-scale optoelectronic integrated systems, broad-band LEDs, and quantum display systems.

Detection of Dexter energy transfer process in interface-type OLED via utilizing the characteristic magneto-electroluminescence response of hot exciton reverse intersystem crossing

The maximum external quantum efficiency of the host-guest-type organic light-emitting diodes (OLEDs) with interface exciplex as the host has been over 36%. However, studies about the energy transfer processes occurring from the host to guest remain lacking. Herein, a strategy is proposed to probe the energy transfer processes in interface-type OLEDs by utilizing the characteristic magneto-electroluminescence (MEL) response from the hot exciton reverse intersystem crossing (T&lt;sub&gt;2,Rub&lt;/sub&gt; → S&lt;sub&gt;1,Rub&lt;/sub&gt;) of rubrene. Specifically, a donor/spacer/accepter (D/S/A)-type interface exciplex device and a D/spacer:&lt;i&gt;x&lt;/i&gt;% Emitter/A (D/S:3% Rubrene/A)-type Rubrene-doped device are fabricated. The Förster resonance energy transfer (FRET) process occurring between the singlet state of the exciplex-host and the singlet state of Rubrene-guest is demonstrated by characterizing the photophysical properties of the donor, accepter, and guest materials. The Dexter energy transfer (DET, T&lt;sub&gt;1,Host&lt;/sub&gt; → T&lt;sub&gt;2,Rub&lt;/sub&gt;) process between the triplet state of the host and the triplet state of guest is visualized by the comparative studying of the current- and temperature-dependent MEL response curves of D/S/A and D/S:3% Rubrene/A devices, respectively. More importantly, the occurrence of the DET process greatly promotes the electroluminescence intensity of the D/S:3% Rubrene/A device. Furthermore, we also investigate the differences in the electroluminescence performance of devices at low temperature to demonstrate again the co-existence of FRET and DET process in the D/S:3% Rubrene/A system. Obviously, this work not only provides a promising strategy for probing the DET process in OLEDs, but also paves a new way for designing high-performance “hot exciton” type OLEDs.