Shallow Trap Research Articles

Unfolding the Impact of H2-Reduction Treatment in Enhancing the Photocatalytic Activity of Rutile TiO2 Based on Photocarriers Dynamics

In the pursuit of efficient titania photocatalysts for water splitting, several strategies have been employed. One of these is reduction of titania (TiO2) via treatment under hydrogen atmosphere, a promising technique to improve the photocatalytic performance. It has been proposed that electron injection induced by reduction on TiO2 demonstrated an improved photocatalytic activity. However, the dynamical processes involving the photogenerated charge carriers in reduced TiO2 have not been fully explored and understood yet. In this work, we employ time-resolved absorption spectroscopy (TAS) and photoluminescence (PL) measurements to unravel the impact of H2 reduction treatment on the photocarriers in rutile TiO2 (R-TiO2). TAS results revealed that the photoexcited electrons are preferentially filling the shallower trap states of reduced R-TiO2, with the lowest energy limit of ∼0.25 eV below the conduction band minimum, much shallower than that of nonreduced R-TiO2 (∼0.62 eV). Furthermore, these favorable effects of H2-reduction resulted in notable increase of long-lived shallow-trapped electrons, substantially extending the lifetimes of electrons and holes. PL measurements strongly support the positive impact of H2 reduction treatment: the NIR emission (∼850 nm) is largely quenched, indicating that the radiative recombination of deep trapped electrons and holes is significantly reduced. The combined PL and TAS results shed light on the impact of H2 reduction on R-TiO2, and this strategy can be potentially useful for further development of other photocatalytic materials.

Facile tailoring of photoluminescence properties of surface-modified TiO2 nanocrystals

Surface modification of metal oxide nanomaterials is one of the promising techniques for tailoring its optoelectronic properties. In this paper, a novel method has been reported for controlling the optical band gap, generation of trapping states and inhibiting the charge carrier’s recombination rate in TiO2 nanocrystals (NCs). It has been achieved through the surface modification of TiO2 NCs using organic ligands such as formamide (FA) and polyethylene glycol (PEG). Investigations reveal that the luminescence properties have also been tuned exhibiting efficient visible light-harvesting photocatalytic activity. All these have been attributed to the interaction between ligands (PEG) and TiO2 forming deep electronic states associated to C-C and C-O bonds which facilitate blue and green wavelength emissions. On the other hand, FA plays an important role as capping ligand and nitriding agent generating shallow and deep trapping states endowed with visible emission at higher wavelength. Furthermore, nitrogen doped functionalized TiO2 NCs (N-TiO2) using urea are prepared solvothermally at temperature as low as 150 °C and pressure higher than 1 atm. Under that conditions, well defined N-TiO2 anatase phase NCs show a band gap of 2.3 eV and exhibit slow electron hole recombination which have been discussed with an emphasis in view of surface modification.

Light Amplification in Fe-Doped CsPbBr3 Crystal Microwire Excited by Continuous-Wave Laser.

Electrically pumped halide perovskite laser diodes remain unexplored, and it is widely acknowledged that continuous-wave (CW) lasing will be a crucial step. Here, we demonstrate room-temperature amplified spontaneous emission of Fe-doped CsPbBr3 crystal microwire excited by a CW laser. Temperature-dependent photoluminescence spectra indicate that the Fe dopant forms a shallow level trap states near the band edge of the lightly doped CsPbBr3 microcrystal. Pump intensity-dependent time-resolved PL spectra show that the introduced Fe dopant level makes the electron more stable in excited states, suitable for the population inversion. The emission peak intensity of the lightly Fe-doped microwire increases nonlinearly above a threshold of 12.3 kW/cm2 under CW laser excitation, indicating a significant light amplification. Under high excitation, the uniform crystal structure and surface outcoupling in Fe-doped perovskite crystal microwires enhanced the spontaneous emission. These results reveal the considerable promise of Fe-doped perovskite crystal microwires toward low-cost, high-performance, room-temperature electrical pumping perovskite lasers.

Defect-rich selenium doped graphitic carbon nitride for high-efficiency hydrogen evolution photocatalysis

Graphitic carbon nitride (g-C3N4) has been demonstrated as a promising non-metal material for photocatalytic hydrogen evolution (PHE), while its photocatalytic activity is greatly limited due to the narrow visible light response-ability and the intrinsic severe charge deep trapping and recombination effects. Herein, a co-functionalized g-C3N4 system by Se doping and nitrogen vacancies modification is developed through a Se vapor-assisted-chemical vapor deposition synthetic strategy. Advanced characterization results revealed that Se dopants promote the visible-light absorption ability of g-C3N4, while nitrogen defects-induced shallow trap states are constructive to improving charge separation/transportation efficiency by effectively retarding the detrimental charge deep trapping and recombination. As a result, the synergistic effect of the Se dopants and nitrogen defects leads to a highly efficient PHE performance of g-C3N4. The integrated engineering strategy and mechanism understanding provided in this work may offer new insights into developing other novel photocatalysts for various applications.

Electronic structure and defects induced luminescence study of phase stabilized t-ZrO2 nanocrystals.

Luminescent tetragonal-ZrO2 nanocrystals were synthesized using an optimized combustion method without post-synthesis annealing and characterized using X-ray diffraction, electron microscopy, Raman, X-ray photoelectron spectroscopy, UV-Visible, photoluminescence spectroscopy, thermoluminescence and vibrating sample magnetometry. The as synthesized t-ZrO2 nanocrystals have a band gap of 4.65 eV and exhibit defect assisted blue emission (CIE coordinates 0.2294,0.1984) when excited with 270 nm. The defect states were qualitatively and quantitatively analyzed using thermoluminescence (TL) after irradiating nanocrystals with gamma and UV radiation at various doses. The TL glow curves show intense emission in the high temperature region from 523-673 K for both UV and gamma irradiated samples; however, another less intense TL peak was also observed in the low temperature region from 333-453 K with gamma irradiation at higher doses, indicating the formation of shallow trapping states. The activation energies, frequency factor and order of kinetics were estimated through the computerized glow curve deconvolution method for the shallow and deep traps for γ and UV- irradiated samples. The present study shows that phase stabilized t-ZrO2 nanocrystals are potential candidates for luminescence-based applications.

The role of capping agents on the trapping levels structure and luminescent emission of SrMoO4 phosphors

In the present work, we investigate the thermoluminescence (TL) and optically stimulated luminescence (OSL) from strontium molybdate SrMoO4 powders designed with different capping agents. The samples were prepared through co-precipitation and processed in a Microwave-Assisted Hydrothermal (MAH) system. The structural, optical, and morphological characteristics were investigated using Raman, Fourier transform infrared spectroscopy (FTIR), DRX, ultraviolet-visible (UV–vis) absorption, and Scanning electron microscopy (SEM). The TL glow curves recorded from as-prepared and irradiated samples with beta particles reveal that their intensity and profile depend on the used capping agent. The trapping depth energy, determined from the TL glows curves, ranges from 1.02 to 2.23 eV for the as-prepared samples and from 0.9 to 2.33 eV for the irradiated phosphors. The residual TL spectra, registered from successive readouts, reveal that the thermal treatment shifts the glow curve to lower temperatures suggesting the formation of shallower trap states. The results reveal that the OSL signal and its behaviors with the radiation dose depending on the employed capping agent. The results show the TL and OSL signal's dependence on the structural properties and support the potential application of SrMoO4 powders as an OSL detector.

Hot Carrier Cooling and Biexciton Dynamics of Anisotropic-Shaped CsPbBr3 Perovskite Nanocrystals

Fast hot-carrier (HC) cooling and the Auger recombination (AR) rate in solar absorbers act as a fundamental barrier toward the harvest of improved solar-energy efficiency. The recent emergence of lead halide perovskite (LHP) has shown enormous potential in high-performance solar cells; however, they are primarily limited to isotropic cubic shapes. It is thus essential to assess whether other anisotropic shapes can be utilized for improving the device’s functionality. Herein, we have studied HC relaxation and AR rates in hexapod CsPbBr3 NCs using ultrafast transient absorption (TA) spectroscopy. Our results indicate a prolonged HC cooling time and bi-exciton lifetime in a hexapod nanostructure compared to cubic CsPbBr3. In coordination with the HC temperature, we further confirm the slower HC relaxation rate in hexapod CsPbBr3 NCs by employing the electron–phonon coupling model, suggesting a retarded decay of longitudinal optical (LO) phonons. We demonstrate that the delocalization of charge carriers in the shallow trap states leads to a reduced overlap of electron and hole wave functions that is responsible for suppressing the bi-exciton AR rate.

Optoelectronic graded neurons for bioinspired in-sensor motion perception.

Motion processing has proven to be a computational challenge and demands considerable computational resources. Contrast this with the fact that flying insects can agilely perceive real-world motion with their tiny vision system. Here we show that phototransistor arrays can directly perceive different types of motion at sensory terminals, emulating the non-spiking graded neurons of insect vision systems. The charge dynamics of the shallow trapping centres in MoS2 phototransistors mimic the characteristics of graded neurons, showing an information transmission rate of 1,200 bit s-1 and effectively encoding temporal light information. We used a 20 × 20 photosensor array to detect trajectories in the visual field, allowing the efficient perception of the direction and vision saliency of moving objects and achieving 99.2% recognition accuracy with a four-layer neural network. By modulating the charge dynamics of the shallow trapping centres of MoS2, the sensor array can recognize motion with a temporal resolution ranging from 101 to 106 ms.

Achieving 17.7% Efficiency of Ternary Organic Solar Cells by Incorporating a High Lowest Unoccupied Molecular Orbital Level and Miscible Third Component

A ternary strategy has been demonstrated as being an effective method to improve the power conversion efficiency (PCE); however, general rules for materials selection are not fully comprehended. Herein, nonfullerene acceptor ITIC‐M and fullerene acceptor PC70BM possessing higher lowest unoccupied molecular orbital (LUMO) and good miscibility with nonfullerene acceptor Y7 are incorporated as third components in the state‐of‐the‐art of PM6:Y7 binary blend. As a result, the device PCE for both ternary devices improves from 16.46% for binary host to 17.73% and 17.67% for ITIC‐M‐ and PC70BM‐based ternary devices, respectively. The higher LUMO of the guest acceptor can play multiple roles to elevate the open‐circuit voltage such as reducing energy‐loss and reverse saturation current, creating less‐localized shallow trap sites along with suppressing charge recombination, and decreasing Urbach energy. Moreover, the good miscibility facilitates an alloy‐like phase in acceptors domain for efficient exciton dissociation and electron transport, which leads to improved short‐circuit current density and fill factor in ternary devices. The results provide a promising approach to realize high‐performance ternary organic solar cells by synergizing the compatible third component with host acceptor.

General Model for Charge Carriers Transport in Electrolyte‐Gated Transistors

AbstractA charge carrier transport model able to describe the typical modes of operation and some non‐ideal ones from electrolyte‐gated field effect transistors and organic electrochemical transistors (OECTs) is proposed. The analysis include the effect of 2D or 3D percolation transport (PT) and the influence of a shallow exponential trap distribution on the transport. Under these considerations, a non‐constant accumulation layer thickness along the channel can be formed, resulting in a non‐constant effective mobility. The accumulation thickness can depict 2D or 3D PT or even a transition between them. This transition can produce a non‐ideal profile between the linear and saturation regimes in the output curve, region in which a lump appears. Other analyzed phenomenon is the non‐linear behavior for low drain voltage in the output curve, even considering an ohmic contact. This phenomenon is attributed to the traps distribution profile into the semiconductor and the thin accumulation layer thickness close to the injection contact. The conditions when the linear field effect mobility is higher or lower than the saturation one is also analyzed. Finally, electrolyte‐gated organic field effect transistors and OECT experimental data are successfully fitted with this model showing its versatility.

Narrow Near-Infrared Emission from InP QDs Synthesized with Indium(I) Halides and Aminophosphine.

Nonpyrophoric aminophosphines reacted with indium(III) halides in the presence of zinc chloride have emerged as promising phosphorus precursors in the synthesis of colloidal indium phosphide (InP) quantum dots (QDs). Nonetheless, due to the required P/In ratio of 4:1, it remains challenging to prepare large-sized (>5 nm), near-infrared absorbing/emitting InP QDs using this synthetic scheme. Furthermore, the addition of zinc chloride leads to structural disorder and the formation of shallow trap states inducing spectral broadening. To overcome these limitations, we introduce a synthetic approach relying on the use of indium(I) halide, which acts as both the indium source and reducing agent for aminophosphine. The developed zinc-free, single-injection method gives access to tetrahedral InP QDs with an edge length > 10 nm and narrow size distribution. The first excitonic peak is tunable from 450 to 700 nm by changing the indium halide (InI, InBr, InCl). Kinetic studies using phosphorus NMR reveal the coexistence of two reaction pathways, the reduction of transaminated aminophosphine by In(I) and via redox disproportionation. Etching the surface of the obtained InP QDs at room temperature with in situ-generated hydrofluoric acid (HF) leads to strong photoluminescence (PL) emission with a quantum yield approaching 80%. Alternatively, surface passivation of the InP core QDs was achieved by low-temperature (140 °C) ZnS shelling using the monomolecular precursor zinc diethyldithiocarbamate. The obtained InP/ZnS core/shell QDs that emit in a range of 507-728 nm exhibit a small Stokes shift (110-120 meV) and a narrow PL line width (112 meV at 728 nm).

Development model of shallow lithologic traps and natural gas accumulation mechanisms in marine deep-water areas: A case study in the qiongdongnan basin, south China sea

Although hydrocarbon gases are widely distributed in the shallow strata of marine deep-water areas, it is generally believed that these shallow gases have little potential to form large gas accumulations due to unfavorable conditions, especially for effective trap development. Based on a comprehensive analysis of the latest geological exploration data of the deep-water areas of the Qiongdongnan Basin, this study reports a large lithologic trap that developed in the shallow Ledong Formation with burial depths of 200–600 m below the seafloor (mbsf). Systematically, this work investigates the development model of the trap and its gas accumulation mechanism. The results indicate that during the Pleistocene, sediment mainly from the southern Kunsong Uplift was transported to the Qiongdongnan Basin due to confined canyon geomorphology and developed a large channelized submarine fan in the deep-water areas. The roof of the submarine fan was cut and eroded and laterally sealed by overlying muddy channels, resulting in a dome-shaped structure, which was further covered by the Pleistocene tight mudstones forming the Ledong lithologic trap. The Yacheng coal-measure source rocks in the deep-water areas had high gas yields, which resulted in increased pressures and promoted deep gas migration into shallow reservoirs along a combined migration pathway including sand strata, structural ridges, faults, fissures, and gas chimneys. The gas accumulated in the Ledong trap as a result of the decreases in temperature and pressure. After the deep gases charged the Ledong strata, migration was blocked by the overburden consisting of Pleistocene tight mudstones, whose seal capacity was significantly enhanced by overlying gas hydrates in the deep-water areas. Meanwhile, the seawater in deep-water areas compacts the underlying cap rocks through its own weight, which enhances the seal capacity of cap rocks. In shallow reservoirs, thermogenic gases may mix with microbial gases from shallow marine source rocks, and some thermogenic gases may be reformed by microorganisms to form secondary microbial gases. The shallow Ledong gas reservoir connects the underlying gas reservoirs and the overlying gas hydrate reservoirs and vertically consists of a continuous hydrocarbon enrichment zone, which significantly expands exploration targets in the deep-water areas of the Qiongdongnan Basin. Additionally, the development model of the shallow Ledong lithologic trap and its gas accumulation mechanism may have general significance for hydrocarbon exploration in marine deep-water areas worldwide.

Trapped Carrier Recombination in Sb2Se3 Polycrystalline Film

Sb2Se3 has recently emerged as a promising material for optic-electronic applications. In this work, trapped carrier recombination in Sb2Se3 was investigated by joint use of time-resolved microwave conductivity (TRMC) and photoluminescence (PL) spectroscopy. trapped carrier thermal excitation into the continuous band was observed in TRMC kinetics. Based on the exponential band tail model, the depth of the trap state, where trapped carriers are released into a continuous band, was estimated to range from 33.0 meV to 110.0 meV at room temperature. Temperature-varying TRMC and PL were further employed to study the influence of temperature on the trapped carrier recombination. Negative thermal quenchings of PL intensity and quantity of thermal emission carriers were observed and can be well explained by the thermal excitation of deep trapped carriers into shallow trap states and the continuous band. Two thermal activation energies of 12.5 meV and 304.0 meV were also revealed. This work is helpful for understanding the trapped carrier recombination process in polycrystalline Sb2Se3 film.

Shallow Traps in Carbon Nitride Quantum Dots to Achieve 6.47 s Ultralong Lifetime and Wavelength‐Tunable Room Temperature Phosphorescence

AbstractRoom temperature phosphorescent (RTP) carbon dots (CDs) have the defects of short lifetime, single wavelength, and poor stability. Most approaches to achieve RTP CDs are based on stabilizing excited triplet state excitons and suppressing nonradiative transitions by providing a rigid environment. The internal structure of CDs has not been followed to address the issue of triplet state exciton quenching. Herein, boron (B) is doped into the framework of carbon nitride quantum dots (CNQDs) to create BN bonds and generate trap state, thus reducing the degree of conjugation and constructing defects. The excited triplet excitons are captured by the defects and stored in the traps from which they escape under thermal activation—this in turn gives rise to an ultralong lifetime RTP. Based on the abovementioned considerations, 6.47 s ultralong‐lifetime deep blue RTP CNQDs with phosphorescent emission wavelength at 418 nm are achieved. This is a significantly longer lifetime than for most deep‐blue RTP CDs. By increasing the conjugation of the precursor, another 1.55 s of green RTP CNQDs at 530 nm is obtained. The difference in lifetime and wavelength between the two phosphorescent CNQDs as well as their excellent stability leads to potential applications in anti‐counterfeiting and information encryption.

Enhanced sensing response of the first polyoxometalate electron acceptor modified MoS2 for NO2 gas detection at room temperature

Here, we introduce polyoxometalate (POMs) electron acceptor into a classical 2-D gas sensing material, MoS2. The MoS2 @PW12 composite nanohydrangeas are prepared by hydrothermal and soaking methods. Then we explore the effect of POMs on sensing property of MoS2 gas sensor for the first time. The research results prove that the sensitivity to 100 ppm NO2 can be effectively promoted to 38.0% via introducing PW12, which is 3.42 times that of pristine MoS2. The promotion can be due to the formation of p-n heterojunction between MoS2 and PW12 and the shallow electron trapping effect of PW12, which can promote carriers migration and restrain their recombination. This work provides a novel thought to develop MoS2-based gas sensors with enhanced sensing sensitivity by the means of utilizing polyoxometalates as electron acceptors.

π-Conjugated In-Plane Heterostructure Enables Long-Lived Shallow Trapping in Graphitic Carbon Nitride for Increased Photocatalytic Hydrogen Generation.

The relatively short-lived excited states, such as the nascent electron-hole pairs (excitons) and the shallow trapping states, in semiconductor-based photocatalysts produce an exceptionally high charge carrier recombination rate, dominating a low solar-to-fuel performance. Here, a π-conjugated in-plane heterostructure between graphitic carbon nitride (g-CN) and carbon rings (Crings ) (labeling g-CN/Crings ) is effectively synthesized from the thermolysis of melamine-citric acid aggregates via a microwave-assisted heating process. The g-CN/Crings in-plane heterostructure shows remarkably suppressed excited-state decay and increased charge carrier population in photocatalysis. Kinetics analysis from the femtosecond time-resolved transient absorption spectroscopy illustrates that the g-CN/Crings π-conjugated heterostructure produces slower exciton annihilation (τ1 = 7.9ps) and longer shallow electron trapping (τ2 = 407.1ps) than pristine g-CN (τ1 = 3.6ps, τ2 = 264.1ps) owing to Crings incorporation, both of which enable more photoinduced electrons to participate in the photocatalytic reactions, thereby realizing photoactivity enhancement. As a result, the photocatalytic activity exhibits an eightfold enhancement in visible-light-driven H2 generation. This work provides a viable route of constructing π-conjugated in-plane heterostructures to suppress the excited-state decay and improve the photocatalytic performance.

2D/2D covalent organic framework/CdS Z-scheme heterojunction for enhanced photocatalytic H2 evolution: Insights into interfacial charge transfer mechanism

• The 2D/2D COF/CdS Z-scheme heterojunction was first reported. • The Z-scheme charge transfer pathways were first identified by Femtosecond transient absorption. • The excellent photocatalytic hydrogen evolution was achieved. • The improved charge separation and hydrogen-evolution kinetics were confirmed. Covalent organic frameworks (COFs) with high crystallinity and flexible designability have been considered as promising candidates for photocatalytic hydrogen evolution. However, the existence of unpropitious exciton effects in COFs leads to poor charge separation, and thus results in low photocatalytic efficiency. Herein, to improve the photoelectron migration efficiency, we designed a 2D/2D organic/inorganic direct Z-scheme COF-based heterojunction (TpTAP/CdS), by the in-situ growing of CdS nanosheets on the COF copolymerized via 2,4,6-tris(4-aminophenyl)-1,3,5-triazine (TAP) and 1,3,5-triformylphloroglucinol (TP). The femtosecond transient absorption (fs-TAS) decay kinetics of TpTAP-COF and TpTAP/CdS further reveal the processes of shallow electron trapping and the recombination of the free photogenerated electron-hole pairs. In particular, the transient absorption traces for TpTAP-COF and TpTAP/CdS normalized to the photoinduced absorption peak can effectively verify the Z-scheme charge transfer between TpTAP-COF and CdS, which could enhance the charge mobility and separation, thus reducing the photocorrosion of CdS. Additionally, ultraviolet photoelectron spectroscopy (UPS), in-situ X-ray photoelectron spectroscopy (XPS), transient photovoltage measurements, and Electron spin resonance spectroscopy (ESR) further confirm the establishment of the internal electric field (IEF). This work demonstrates the important role of COFs in the construction of 2D/2D organic/inorganic direct Z-scheme heterojunctions and offers a new avenue to explain the criticality of dynamics of the photogenerated carriers for the construction of Z-scheme heterojunctions.

Cr dopant induced tailoring of intrinsic defects and trap distribution in MgAl2O4 nanocrystals: electron spin resonance and thermoluminescence

Thermoluminescence (TL) response of γ-irradiated Cr3+ doped MgAl2O4 nanocrystals is studied to investigate the impact of dopant ions on intrinsic defects and trap distribution. At low doping concentration, the broad TL glow curve has a dominant incomplete peak attributed to deep F+ centers around 673 K and contribution from shallow , , and trapping states in low temperature region. TL glow curve intensity and trap distribution is found to be influenced with increase in Cr doping concentration. Electron spin resonance spectra show the interaction of electron spins at paramagnetic F+/V− centers with isolated and paired Cr3+ ions with increase in Cr doping concentration. Cr3+ ions doped at octahedral sites are found to be perturbed by the presence of , , etc defect centers and may cause the formation of Cr associated defect clusters at higher doping concentration. A trapping mechanism is proposed as per the TL response obtained upon γ-irradiation to comprehend the intertrap charge transfer among various shallow and deep trapping states.

Shallow traps-induced ultra-long lifetime of metal halide perovskites probed with light-biased time-resolved microwave conductivity

Metal halide perovskites have emerged as promising candidates for next-generation optoelectronics. However, the present understanding of their recombination processes and trap states within the devices are still limited, which is also inevitable in the state-of-the-art perovskite solar cells with multiple passivation strategies and various additives involved. Recent works have also demonstrated that metal cations incorporated perovskites could potentially reduce the non-radiative losses and improve the device performance to some extent. However, the underlying “doping” mechanism is not clear. In this work, we systematically investigated the trap-induced ultra-long carrier lifetime of the metal cation incorporated perovskites and found that some specific cations could extend the carrier lifetime up to ∼100 μs, which could be correlated with the formation of shallow trap states. In addition, such shallow trap-mediated charge dynamics could be effectively probed with light-biased time-resolved microwave conductivity technique, which provides additional information to conventional time-resolved photoluminescence.

Probing the Genuine Carrier Dynamics of Semiconducting Perovskites under Sunlight.

Understanding the nature of photogenerated carriers and their subsequent dynamics in semiconducting perovskites is important for the development of solar cell materials and devices. However, most ultrafast dynamic measurements on perovskite materials were conducted under high carrier densities, which likely obscures the genuine dynamics under low carrier densities in solar illumination conditions. In this study, we presented a detailed experimental study of the carrier density-dependent dynamics in hybrid lead iodide perovskites from femtosecond to microsecond using a highly sensitive transient absorption (TA) spectrometer. From the dynamic curves with low carrier density in the linear response range, we observed two fast trapping processes that occurred in less than 1 ps and tens of picoseconds, attributed to the shallow traps, and two slow decays with lifetimes of hundreds of nanoseconds and longer than 1 μs, related to the trap-assisted recombination and trapping at deep traps. Further TA measurements clearly show that PbCl2 passivation can effectively reduce both shallow and deep trap densities. These results provide insights into the intrinsic photophysics of semiconducting perovskites with direct implications for photovoltaic and optoelectronic applications under sunlight.