Balanced Carrier Transport Research Articles

Utilization of Nanoporous Nickel Oxide as the Hole Injection Layer for Quantum Dot Light-Emitting Diodes.

Nickel oxide (NiOx) has been extensively investigated as the hole injection layer (HIL) for many optoelectronic devices because of its excellent hole mobility, high environmental stability, and low-cost fabrication. In this research, a NiOx thin film and nanoporous layers (NPLs) have been utilized as the HIL for the fabrication of quantum dot light-emitting diodes (QLEDs). The obtained NiOx NPLs have spongelike nanostructures that possess a larger surface area to enhance carrier injection and to lower the turn-on voltage as compared with the NiOx thin film. The energy levels of NiOx were slightly downshifted by incorporating the nanoporous structure. The amount of Ni2O3 species is higher than that of NiO in the NiOx NPL, confirming its good hole transport ability. The best QLED was achieved with a 30 nm thick NiOx NPL, exhibiting a maximum brightness of 68 646 cd m–2, a current efficiency of 7.60 cd A–1, and a low turn-on voltage of 3.4 V. More balanced carrier transport from the NiOx NPL and ZnO NPs/polyethylenimine ethoxylated (PEIE) is responsible for the improved device performance.

Over 16.5% efficiency in ternary organic solar cells by adding an alloyed acceptor with energy transfer process

Ternary organic solar cells (OSCs) based on ternary blends of light-absorption materials are simple and impactful strategies to boost the power conversion efficiency (PCE) of single-junction OSCs. In the work, a non-fullerene molecule ITIC with a medium bandgap (1.59 eV) is added to PM6:Y6 binary system as the third component. Compared with the 15.5% and 9.2% of PM6:Y6 and PM6:ITIC binary OSCs, respectively, PM6:Y6:ITIC ternary OSCs achieve a PCE of 16.6% by incorporating 5 wt% ITIC that results from simultaneously enhanced open-circuit voltage of 0.879 V, short-circuit current density of 25.50 mA cm−2 and fill factor of 74.20%. The extended absorption, enhanced fluorescence resonance energy transfer, balanced carrier transport with increased electron and hole mobility, and reduced energy loss in PM6:Y6:ITIC ternary films enhance the photovoltaic performance of ternary OSCs. The work illustrates that adding an alloyed second acceptor with efficient energy transfer processes in ternary OSCs has great potential to further improve the performance of OSCs.

Use of Hybrid PEDOT:PSS/Metal Sulfide Quantum Dots for a Hole Injection Layer in Highly Efficient Green Phosphorescent Organic Light-Emitting Diodes.

In this study, we have synthesized the molybdenum sulfide quantum dots (MoS2 QDs) and zinc sulfide quantum dots (ZnS QDs) and demonstrated a highly efficient green phosphorescent organic light-emitting diode (OLED) with hybrid poly (3,4-ethylenedioxythiophene)/poly (styrenesulfonate) (PEDOT:PSS)/QDs hole injection layer (HIL). The electroluminescent properties of PEDOT:PSS and hybrid HIL based devices were explored. An optimized OLED based on the PEDOT:PSS/MoS2 QDs HIL exhibited maximum current efficiency (CE) of 72.7 cd A−1, which shows a 28.2% enhancement as compared to counterpart with single PEDOT:PSS HIL. The higher device performance of OLED with hybrid HIL can be attributed to the enhanced hole injection capacity and balanced charge carrier transportation in the OLED devices. The above analysis illustrates an alternative way to fabricate the high efficiency OLEDs with sulfide quantum dots as a HIL.

Enhanced performance of white organic light-emitting devices based on ambipolar white organic single crystals

Organic single crystals are highly promising for applications in optoelectronic devices because of their higher mobility and thermal stability than amorphous thin films. Although white organic single crystals have been fabricated by the double-doped method and applied to realize white organic light-emitting devices (WOLEDs), the unbalanced carrier transport properties of the unipolar crystals severely limit the device performance. Here, ambipolar white organic single crystals are obtained by using mixed p- and n-type molecules as an ambipolar host for the red and green dopants. The white crystal with balanced carrier transport and balanced blue, green, and red emission intensity was applied to the single-crystal WOLEDs. The highest brightness of 1956 cd m−2 and the current efficiency of 1.31 cd A−1 are achieved, which are the best performance of the single-crystal WOLEDs reported to date. A high color rendering index is obtained, which varies between 82 and 87 with increasing driving current. It is expectable that this strategy would support the practical applications of organic single crystal-based OLEDs.

Solvent‐Regulated Electronic Structure and Morphology of Inorganic Hole Injection Layers for Efficient Quantum Dot Light‐Emitting Diodes

Inorganic charge transport layers (CTLs) have been proven to be effective for improving the stability of electroluminescent devices. However, the effective regulation of electronic structure for solution‐processed inorganic CTLs is still challenging by doping or interface engineering, and the film morphology is usually poor due to surface aggregation. Herein, the energy level and mobility of inorganic phosphomolybdic acid (PMA) hole injection layers (HILs) are regulated by adjusting the polarity of solvents, and the resulting inorganic HILs with proper electronic structure act as an energy ladder to better promote hole injection, thereby achieving balanced carrier transport in quantum dot light‐emitting diodes (QLEDs). Meanwhile, the surface morphology of the inorganic PMA film is also improved using solvents with high boiling points, which minimizes the surface tension and is conducive to the formation of smooth and pinhole‐free films. As a result, the devices using PMA dissolved in n‐butanol with a lower polarity exhibit a peak external quantum efficiency (EQE) of 19.2%, which is 3.6 times higher than that of QLEDs using PMA obtained from acetone solvent with a higher polarity. Herein, a general method for the deposition of high‐quality HILs for the fabrication of solution‐processed inorganic functional layers and optoelectronic devices is provided.

Controllable molecular doping in organic single crystals toward high-efficiency light-emitting devices

Organic single-crystalline semiconductors have drawn significant attention in the area of organic electronic and optoelectronic devices due to their superiorities of highly ordered structure, high carrier mobility and low impurity content. Molecular doping technique has made great progress in improving device performance via optimizing the optical and electrical properties of organic semiconductors. In particular, this technique has been attempted by taking fluorescent dye-molecules as the emissive dopants to tune emission color and improve device performance of organic single crystals. Up to now, there are few reports about the use of molecular doping in organic single crystals to optimize their intrinsic electrical properties. Here, we have introduced the controllable molecular doping as a feasible approach toward manipulating charge carrier transport properties of organic single crystals. Upon optimization of doping concentration, balanced carrier transport can be realized in 5,5′-bis(4-trifluoromethyl phenyl) [2,2’] bithiophene (P2TCF3)-doped 1,4-bis(4-methylstyryl) benzene (BSB–Me) crystals. Organic light-emitting devices (OLEDs) based on these doped crystals achieve a maximum luminance of 423 cd/m2 and current efficiency of 0.48 cd/A. It demonstrates that high-efficiency crystal-based OLEDs are of great significance for the development of organic electronics, especially for display and lighting applications.

Isotope Effect of Host Material on Device Stability of Thermally Activated Delayed Fluorescence Organic Light‐Emitting Diodes

Organic light‐emitting diodes (OLEDs) exhibiting thermally activated delayed fluorescence (TADF) have attracted great interest because of their excellent exciton harvesting ability in electroluminescence (EL). While TADF‐OLEDs show a high EL efficiency, the device operational stability is not necessarily satisfactory for commercial applications. Herein, the isotope effect of the host material on the device operational stability in TADF‐OLEDs is investigated. It is unveiled that the deuterated host, i.e., PYD2Cz‐d16, forms a denser film than that of the nondeuterated host, PYD2Cz, demonstrating enhanced stable amorphous nature and balanced carrier transport properties. In green TADF‐OLEDs, the PYD2Cz‐d16‐based OLED considerably lengthens the device operational stability of LT95 (95% of the initial luminance) to ≈140 h at an initial luminance of 1000 cd m−2, which is 1.7 times longer than that of PYD2Cz. Device stabilities of blue TADF‐OLEDs with PYD2Cz‐d16 as a host are also demonstrated with an enhancement of 2 times in LT50 at an initial luminance of 1000 cd m−2. It is suggested that the deuterated materials have a positive effect on the device stability in not only TADF‐OLEDs, but also all other OLEDs having fluorescence and phosphorescence emitters.

Recent developments on organic single crystal-based light-emitting devices

<p indent="0mm">Organic single crystals with low impurity content and long-range periodic order usually present high carrier mobility, which have attracted increasing interest in the field of optoelectronic devices, such as organic light-emitting transistors, organic field-effect transistors (OFETS), optically pumped lasers, and organic light-emitting devices (OLEDs). They are recognized as ideal materials for OLEDs because of their better thermal stability and higher carrier mobility compared to their amorphous counterparts. This review focuses on the recent developments of organic single crystal-based OLEDs from four aspects, including a summary of widely used organic single crystals, crystal growth methods, fabrication strategies for organic single-crystal OLEDs, and structure optimizations of the devices. Before the device fabrication, it is very important to choose suitable crystal materials with prominent optoelectronic properties. The crystal materials can be classified into three different subjects according to their charge transporting properties, including P-type, N-type, and ambipolar. These crystal materials are summarized with three major properties of charge mobility, emission peak position, and energy level structure. The second is the growth methods for growing organic single crystals with low impurity and defects. Based on the traditional vapor-processing and solution-processing method, some novel crystal growth strategies have been developed for large-area organic single crystals with controllable thickness down to one molecular layer. In view of the fabrication of organic single crystal-based OLED devices, the template stripping method has been introduced to fabricate organic single crystal-based OLEDs with improved contact between metallic electrodes and crystals. Based on this method, organic single crystal-based OLEDs can be realized with bright surface emission and polarized EL behaviors. Molecular doping technique is also employed for the fabrication of crystal-based OLEDs with three primary colors. In addition, WOLEDs based on double-doped organic single crystals are also discovered with high color rendering index, indicating strong potential in the display and lighting field. Later, ambipolar crystals prepared by doping N-type molecules into a P-type crystal matrix for equal mobility are achieved for OLEDs with a recorded brightness and efficiency. Organic single crystal-based OLEDs have made great progress, however, the device performance still lags far behind the traditional amorphous thin-film OLEDs and faces enormous challenges. This review then introduced several potential strategies that can further improve the performance of organic single crystal-based OLEDs in four aspects: Designing new organic single crystal materials with high solid-state luminous efficiency and balanced carrier transport, exploring new growth strategies for precise control of organic single crystal thickness in combination with the semiconductor manufacturing technology, developing various host-guest doping systems for effectively promoting the efficiency of organic single crystal-based OLEDs, and further optimizing the device structure with improved energy levels. In conclusion, organic single crystals have made remarkable progress in the development of electronic and optoelectronic devices, especially for organic single crystal-based OLEDs, which can be ascribed to the development of new material designs, innovative crystal growth methods, and the revolution of device fabrication. Many efforts are required to seek novel strategies for the improvement of organic single crystal-based OLEDs which are expected to be great potential in optoelectronic devices.

Bifunctional Bis‐benzophenone as A Solid Additive for Non‐Fullerene Solar Cells

AbstractSimultaneously improving efficiency and stability is critical for the commercial application of non‐fullerene acceptor polymer solar cells (NFA‐PSCs). Multifunctional solid additives have been considered as a potential route to tune the morphology of the active layer and optimize performance. In this work, photoinitiator bifunctional bis‐benzophenone (BP‐BP) is used as a solid additive, replacing solvent additives, in the PBDB‐T:ITIC NFA system. With the addition of BP‐BP, the intermolecular π–π stacking of PBDB‐T and morphology is improved, leading to more balanced carrier transport and more effective exciton dissociation. Devices fabricated with BP‐BP show a power conversion efficiency (PCE) of 11.89%, with enhanced short‐circuit current (Jsc), and fill factor (FF). Devices optimized with BP‐BP show excellent reproducibility, insensitivity to thickness, and an improved thermal stability under atmospheric conditions without encapsulation. This work provides a new strategy for the application of solid additives in NFA‐PSCs.

High‐Power‐Efficiency White Thermally Activated Delayed Fluorescence Diodes Based on Selectively Optimized Intermolecular Interactions

AbstractBesides low cost and environmental sustainability, high power efficiency is an essential condition for daily lighting applications, and one of main challenges for thermally activated delayed fluorescence (TADF) white organic light‐emitting diodes (WOLED). Here, it is demonstrated that power efficiency can be improved through accurately modulating intermolecular interactions. An asymmetrical phosphine oxide (PO) molecule named 246DBFTPO is constructed, in which the steric hindrance and inductive effect of PO groups restrain π–π stacking but form continuous intermolecular hydrogen bond networks. The steric anisotropy of PO groups leads to the heterogeneous molecular distribution in 246DBFTPO matrix, accompanied by the homogeneous intermolecular interactions. Compared to symmetrical and semi‐symmetrical PO congeners, 246DBFTPO provides balanced carrier transport, efficient host–dopant and dopant–dopant energy transfer, and effective quenching suppression. Based on its electron mobility of 10−5 cm2 V−1 s−1 and a 90% photoluminescence quantum yield of its dually doped white TADF film, 246DBFTPO is simultaneously competent as host and electron transporting material in a trilayer single‐EML full‐TADF WOLED, leading to a record power efficiency of 76.7 lm W−1.

TADF material with non-conjugated rigid donor for high-performance full-color phosphorescent OLEDs: Effects of triplet harvest and charge transport on efficiency

Host materials play a crucial role in developing highly efficient OLEDs, of which universal host materials for full-color OLEDs are in great demand. Herein, two wide band-gap thermally activated delayed fluorescence (TADF) host materials based on diphenylsulfone derivatives were developed by rationally tuning the TADF characteristic and charge transport ability through electron-donor engineering. Owning to the non-conjugated rigid donor 9,9-dimethylacridine, mSOAD showed obvious superiority in pronounced TADF effect with an extra small singlet-triplet energy split of 0.02 eV and balanced carrier transport properties. Full-color phosphorescent OLEDs based on mSOAD were achieved with impressive efficiencies of 65.52 cd/A, 66.51 lm/W and 19.00% for green OLED, 36.19 cd/A, 32.46 lm/W and 16.7% for blue OLED and 32.65 cd/A, 30.99 lm/W, and 20.31% for red OLED, respectively. Our results revealed the key effect of efficient triplet harvest and balanced charge transport ability of TADF host materials in high efficiency and low efficiency roll-off in OLEDs.

High-performance sky-blue phosphorescent organic light-emitting diodes employing wide-bandgap bipolar host materials with thermally activated delayed fluorescence characteristics

Abstract Up to date, several kinds of thermally activated delayed fluorescence (TADF) host molecules have been rapidly developed to fulfill the increasing demand of high-efficiency phosphorescent organic light-emitting diodes (PHOLEDs). Herein, three wide-bandgap TADF materials BPCN-Cz2Ph, BPCN-2Cz, and BPCN-3Cz are newly designed and synthesized as host materials for sky-blue PHOLEDs. By modulation of carbazole-units in the molecular skeleton, we find that the optimized molecules can realize both high triplet energies and balanced carrier transport properties with obvious TADF properties. The sky-blue PHOLEDs with ultralow phosphor doping ratio employing BPCN-Cz2Ph, BPCN-2Cz, and BPCN-3Cz as host materials demonstrate really high performance with alleviated roll-offs and achieve impressive current efficiencies (CEs) of 46.5 cd A−1, 50.0 cd A−1, and 34.5 cd A−1, power efficiencies (PEs) of 40.6 lm W−1, 46.8 lm W−1, and 34.8 lm W−1, and external quantum efficiencies (EQEs) of 22.2%, 24%, and 15.8%, respectively. More encouragingly, even at an applied luminance of 1000 cd m−2, the EQEs could maintain high levels of 21.0%, 21.5% and 12.8%, respectively, which represents the potential utility value of the new family of these molecules in blue PHOLEDs. Our molecular design strategy provides a practical way to construct promising wide-bandgap TADF host materials with an excellent combination of TADF property, high triplet energy, and balanced carrier-transporting ability for high-performance devices.

Broad spectrum light-trapping ternary polymer solar cells based on self-assembled nano-ridged active layer

Ternary blend polymer solar cells (TPSCs) comprising one donor and two fullerene acceptors is efficient method for improving the power conversion efficiency (PCE). In this paper, the PTB7-Th-based TPSCs which is incorporating PC70BM and PC60BM as mixed acceptors are fabricated and investigated. Impressively, the remarkable self-assembled nano-ridged (SANR) structures are discovered in the active layer with the weight ratio of 50% PC60BM in fullerenes. Thanks to the enlarged interface area, enhanced light absorption and balanced carrier transport, the PTB7-Th:PC70BM:PC60BM TPSCs with the SANR active layer gives an optimal PCE of 9.68%. In addition, it is worth emphasizing that by combining the textured-ZnO with the SANR active layer, a double ridge superimposed system (DRSS) with broad spectrum light trapping characteristic is constructed, which can further enhance the light absorption of the devices. Finally, benefiting from the further increase in short circuit current density (Jsc), the PTB7-Th:PC70BM:PC60BM TPSCs with the DRSS gives an optimal PCE of 10.68%. This work provides a feasible ternary strategy to increase the devices performances and is proved be a simple and efficient strategy for fabricating PTB7-Th:PC70BM:PC60BM TPSCs with SANR active layer.

An efficient CsPbBr3 perovskite light-emitting diode by employing 1,3,5-tri(m-pyrid-3-yl-phenyl)benzene as a hole and exciton blocking layer

An efficient perovkite light-emitting diode (PeLED) is fabricated by incorporating 1,3,5-tri (m-pyrid-3-yl-phenyl)benzene (TmPyPB) between the emitting layer (EML) and the electron transporting layer (ETL), where TmPyPB plays an indispensable blocking effect on both excitons and holes. It shows a maximum current efficiency of 9.37 cd/A, and the corresponding external quantum efficiency (EQE) of 2.42% with a saturated green color Commission International de I'Eclairage (CIE1993) coordinated of (0.1279, 0.7951) under a driving voltage of 6 V. Meanwhile, the operational lifetime of the TmPyPB-based PeLED is improved to about 2.6-fold to that of the one with only the traditional ETL of aluminum 8-hydroxyquinolinate (Alq3). The enhancements of electroluminescence (EL) performance are mainly attributed to better confinement of both the holes and the excitons in the EML, and more balanced carrier transportation in the TmPyPB-based PeLED. This work offers a feasible strategy to develop high performance optoelectronic devices.

The effect of the exciplex heterojunction interlayer on efficiency roll-off in non-doped blue phosphorescent organic light-emitting diodes

High exciton density will cause triplet-triplet annihilation (TTA)/triplet-polaron annihilation (TPA) and result in low efficiency of blue phosphorescent organic light-emitting diodes (OLEDs) at high voltage. The carriers and excitons can be effectively localized through the interfacial effect generated by the energy level structure of heterojunction interlayer , which can extend the recombination zone (RZ) and disperse excitons in the emitting layer (EML). In order to enhance the local effect on excitons, we introduce exciplex material as the spacer layer (SPL) in heterojunction interlayer. When the thickness of SPL is 3 nm, device C1 with a exciplex SPL (TCTA:TPBi) obtains the optimal efficiency roll-off and the maximum luminance of 4434 cd/m2. The main reason can be attributed to the fact that the triplet energy level of SPL material in device C1 is lower than that in device C3 with a exciplex SPL (mCP:TPBi) as shown in the photoluminescence (PL) spectra of exciplexes, and device C1 has more balanced carrier transport than device C2 with a exciplex SPL (TAPC:TPBi). The optimization of SPL material and thickness can effectively improve the efficiency of OLEDs by localizing excitons while dispersing the exciton density and reducing efficiency roll-down.

Highly Efficient Blue Electroluminescent Materials Based on Phenanthro[9,10-d] imidazole

Phenanthro[9,10-d]-imidazole( PI) unit has attracted extensive attentions in organic optoelectronic field due to its intrinsic wide band gap,high luminescence efficiency,good thermal stability,balanced charge carrier injection and transport property as well as low fabrication cost. In this manuscript,the recently reported blue electroluminescent PI derivatives were reviewed. The structure characteristics of PI were demonstrated,and the structure-property relationships of some PI derivatives were summarized systemically. At last,all the reported highly efficient nondoped deep blue emitters were summed up in order to comprehensively evaluate the potentials of PI derivatives in organic light emitting diodes( OLEDs) in the future.

Perovskite Solar Cells: Low‐Dimensional Perovskites with Diammonium and Monoammonium Alternant Cations for High‐Performance Photovoltaics (Adv. Mater. 35/2019)

In article number 1901966, Guichuan Xing, Yanlin Song, and co-workers present a new low-dimensional perovskite based on 1,4-butanediamine (BEA), with the alternating ordered of diammonium and monoammonium cations in the interlayer space. Taking advantage of the short layer spacing and hydrogen bonding, a barrier-free and balanced carrier-transport pathway with an enhanced carrier-diffusion mechanism is proposed. Due to the hydrophobicity of BEA, the new low-dimensional perovskite exhibits excellent stability.

Low-Dimensional Perovskites with Diammonium and Monoammonium Alternant Cations for High-Performance Photovoltaics.

Low-dimensional Ruddlesden-Popper (LDRP) perovskites are a current theme in solar energy research as researchers attempt to fabricate stable photovoltaic devices from them. However, poor exciton dissociation and insufficiently fast charge transfer slows the charge extraction in these devices, resulting in inferior performance. 1,4-Butanediamine (BEA)-based low-dimensional perovskites are designed to improve the carrier extraction efficiency in such devices. Structural characterization using single-crystal X-ray diffraction reveals that these layered perovskites are formed by the alternating ordering of diammonium (BEA2+ ) and monoammonium (MA+ ) cations in the interlayer space (B-ACI) with the formula (BEA)0.5 MAn PbnI3n+1 . Compared to the typical LDRP counterparts, these B-ACI perovskites deliver a wider light absorption window and lower exciton binding energies with a more stable layered perovskite structure. Additionally, ultrafast transient absorption indicates that B-ACI perovskites exhibit a narrow distribution of quantum well widths, leading to a barrier-free and balanced carrier transport pathway with enhanced carrier diffusion (electron and hole) length over 350 nm. A perovskite solar cell incorporating BEA ligands achieves record efficiencies of 14.86% for (BEA)0.5 MA3 Pb3 I10 and 17.39% for (BEA)0.5 Cs0.15 (FA0.83 MA0.17 )2.85 Pb3 (I0.83 Br0.17 )10 without hysteresis. Furthermore, the triple cations B-ACI devices can retain over 90% of their initial power conversion efficiency when stored under ambient atmospheric conditions for 2400 h and show no significant degradation under constant illumination for over 500 h.

New bipolar host materials based on methyl substituted pyridazine for high-performance green and red phosphorescent OLEDs

In this work, two host materials, namely DAMP and DCMP were designed and synthesized based on 4,5-dimethylpyridazine and triphenylamine or carbazole. These two compounds exhibit good thermal stability, suitable highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels and balanced carrier transport properties. Green phosphorescent organic light-emitting devices (PhOLEDs) based on DAMP and DCMP exhibit excellent performance with the maximum external quantum efficiencies (EQEs) of 19.5% and 22.2%, respectively. At the luminance of 1000 cd/m2, the EQE of the device based on DCMP can still reach to 21.4%. Besides, red PhOLEDs hosted by DAMP and DCMP also showed satisfied performance, with the maximum EQE of 15.3% and 20.0%, respectively. These results suggest that DAMP and DCMP are promising host materials for green and red PhOLEDs.

47-Fold EQE improvement in CsPbBr3 perovskite light-emitting diodes via double-additives assistance

All-inorganic cesium halide perovskite materials are intensively investigated due to their excellent photoelectric characteristics, but poor film coverage, unbalanced charge carrier transporting and insufficient exciton harvesting are remaining challenges to be overcome in order to achieve high electroluminescent (EL) performance in perovskite light-emitting diodes (PeLEDs). Here we show that these problems can be solved by introducing both a phosphorescent sensitizer (FIrpic) and an electron transporting material (TmPyPB) into all-inorganic cesium halide perovskite (CsPbBr 3 ). And highly efficient green PeLEDs with full coverage CsPbBr 3 :TmPyPB:FIrpic film as the emissive layer have been achieved, exhibiting the maximum luminance of 37784 cd/m 2 , the maximum current efficiency of 22.6 cd/A and the corresponding maximum external quantum efficiency (EQE) of 5.85%, where the EQE is 48-fold to that of bare CsPbBr 3 PeLEDs. The enhanced EL performance is attributed to less non-radiative current leakage, better film surface passivation effect, balanced charge carrier injection and transportation, as well as better exciton harvesting. It is believed that our work will provide an effective strategy to further improve EL performance of PeLEDs via better exciton harvesting. • Excellent enhanced electroluminescent performances were realized in CsPbBr 3 :TmPyPB:FIrpic based PeLEDs. • Pinhole-free and continuous CsPbBr 3 :TmPyPB:FIrpic perovskite films was achieved. • The current leakage was largely reduced. • More balanced charge carrier transporting behavior in perovskite emitting layer was reached. • Improved exciton harvesting was realized due to Förster and Dexter energy transfer processes.