Charge Carrier Dynamics Research Articles

Light-induced micro-strain regulation and charge carrier dynamics of (FA0.83MA0.17)0.95Cs0.05Pb(I0.83Br0.17)3 hybrid perovskite films

Light-induced strategies are crucial for deciding the physical and chemical properties of organometal halide perovskite materials and their photovoltaic devices. Herein, the triple cation ((FA0.83MA0.17)0.95Cs0.05Pb(I0.83Br0.17)3) hybrid perovskite films have been fabricated using a simple solution-processed method. These films were illuminated by blue light (417 nm) for different time durations and characterized for structural, surface morphological, optical, and charge carrier dynamics. Under illumination conditions, a reduction in lattice micro-strain has been observed. The enhanced optical absorbance and reduced non-radiative recombination have also been monitored in light-illuminated perovskite films. Further, time-resolved photoluminescence (TRPL) and ultra-fast transient absorption spectroscopy (TAS) measurements have been performed to study the charge carrier dynamics. TRPL results show that the average lifetime of charge carriers has increased from 3 ns to 19 ns upon continuous light illumination conditions. Further, the recombination time of the charge carriers decreased from 226 ps to 66 ps upon continuous light illumination for 30 min. This study suggests that light-induced experiments on perovskite films can be utilized for micro-strain regulation and modulation of their charge carrier dynamics for future perovskite solar cell applications.

Charge particle dynamics and electrochemical behaviour of SrTiO3-δ as anode material for IT-SOFC applications

SrTiO3-δ is a well-known metal oxide with cubic perovskite structure. In this work, we have synthesized SrTiO3-δ via conventional solid-state reaction route (SSR) and studied its electrochemical behaviour in three different pH media viz. 1 M aqueous solution of Na2SO4, (pH 7, neutral medium), KOH (pH 14, basic medium) and 0.5 M solution of H2SO4 (pH 1, acidic medium). The cubic phase with lattice constant, a = 3.905 Å is confirmed through XRD measurements. The electrical characterization of the sample was done in the frequency range 1Hz to 1 MHz and temperature range 25 oC–700 oC. The dynamics of the charged particles in the sample was studied using Jonscher power law. The scaling behaviour of the system has been investigated to understand the conduction mechanism. Further, charge carrier kinetics was also studied to understand the ionic contribution. Electrocatalysis was studied by cyclic voltammetry confirming the redox process in neutral and basic media, which was further confirmed in the XPS study. A better redox coupling occurs that was related to the Ti d-orbital and the O p-orbital interaction. The conductivity and catalytic properties of these materials indicated their use in different applications such as in fuel cells, sensors as well as in electrochemical devices.

Temperature dependent charge carrier dynamics in 2D ternary Cu2MoS4 nanoflakes: An effect of electron-phonon coupling.

Two-dimensional transition metal chalcogenides (2D TMCs) like MoS2, WS2 etc., have established significant dominance in the field of nanoscience and nanotechnology, owing to their unique properties like strong light-matter interaction, high carrier mobility, large photo-responsivity etc. Despite the widespread utilization of these binary TMCs, their potential in the advancement of the optoelectronic research is limited due to the constraints in band tuning and charge carrier lifetime. To overcome these limitations, ternary transition metal chalcogenides have emerged as promising alternatives. Although, the optical properties of these materials have never been explored properly. Herein, we have investigated one such promising member of this group, Cu2MoS4 (CMS) using both steady state and time-resolved spectroscopic techniques. The material exhibits a broad range of visible light absorption, peaking at 576nm. Photoluminescence spectroscopy confirmed the presence of both band gap emission and trap state-mediated emissions. Transient absorption spectroscopy unraveled the excited state charge carrier dynamics of CMS in sub-ps timescale, upon irradiation of visible light. We found significant influence of the trap mediated recombination, while Auger process being dominant at high charge density. We extended our study in a wide temperature range (5-300K), which reveals the impact of electron-phonon coupling strength on the band gap and charge carrier dynamics of this material. This detailed study would draw more attention toward the unexplored optical properties of ternary 2D chalcogenides and will open new avenues for the construction of 2D material-based optical devices.

Bayesian optimization approach to quantify the effect of input parameter uncertainty on predictions of numerical physics simulations

An understanding of how input parameter uncertainty in the numerical simulation of physical models leads to simulation output uncertainty is a challenging task. Common methods for quantifying output uncertainty, such as performing a grid or random search over the model input space, are computationally intractable for a large number of input parameters represented by a high-dimensional input space. It is, therefore, generally unclear as to whether a numerical simulation can reproduce a particular outcome (e.g., a set of experimental results) with a plausible set of model input parameters. Here, we present a method for efficiently searching the input space using Bayesian optimization to minimize the difference between the simulation output and a set of experimental results. Our method allows explicit evaluation of the probability that the simulation can reproduce the measured experimental results in the region of input space defined by the uncertainty in each input parameter. We apply this method to the simulation of charge-carrier dynamics in the perovskite semiconductor methyl-ammonium lead iodide (MAPbI3), which has attracted attention as a light harvesting material in solar cells. From our analysis, we conclude that the formation of large polarons, quasiparticles created by the coupling of excess electrons or holes with ionic vibrations, cannot explain the experimentally observed temperature dependence of electron mobility.

Investigation on buried interfacial charge carrier dynamics of the MAPbI3/NiO interface by mismatch strain and termination

Organic-inorganic halide perovskite solar cells (PSCs) have attracted significant attention due to their low cost, simple fabrication process, and rapid improvement in photovoltaic performance. NiO is often considered as a potential hole transport layer (HTL) in these PSCs owing to its wide band gap and deep valence band level. However, uncertainties remain regarding the interfacial charge carrier dynamics at the perovskite/HTL interface induced by the interfacial mismatch strain and terminal configuration. Herein, typical MAPbI3/NiO interfacial terminal configurations (MAI-Ni, MAI-O, PbI-Ni, PbI-O) with strain-configured interfaces were explored by first-principle and device simulation. The results indicate that the binding energy decreases, the carrier transport efficiency increases, and the valence band offset (VBO) decreases as the interfacial atomic configuration of the perovskite surface changes from MAI to PbI. Meanwhile, the compressive strain applied on the perovskite surface also increases the interfacial VBO. The J-V curves and energy band of the PSCs show that the device performance tends to enhance first and then decrease as the positive VBO of the MAPbI3/NiO interface increases. Thus, the strain and termination configuration could modulate the device's photovoltaic performance, which is dependent on the energy band bending caused by the strain and termination configuration. This work provides a valuable understanding of the MAPbI3/NiO interface and contributes new strategies to interface optimization for further improving the photoelectric conversion efficiency of PSCs.

Comparing the loss of charge carrier generation with the loss of V OC at low temperatures in organic bulk-heterojunction blends

Abstract We estimate the temperature dependence of charge carrier generation in P3HT:ICBA and PTB7:PCBM using continuous-wave photoinduced absorption. For P3HT:ICBA, the generation rate increases fivefold from 79 K to ca 250 K, above which it saturates. We compare this to the temperature dependence of open-circuit voltage (V OC) which at low temperatures shows a decrease with decreasing temperatures, in disagreement with the typically expected linear rise. This voltage loss is too large to be explained by the decrease of generation with decreasing temperature. For PTB7:PCBM the dominant species has a generation rate increasing from 90 to 150 K, after which it decreases. For PTB7:PCBM there is no decrease in V OC at low temperatures. Our findings support the lack of correlation between the decrease in V OC and a decrease in generation rate. We conclude that the loss of V OC does not originate in charge carrier dynamics in the bulk material, but is due to contact effects.

Broadband and High‐Performance Photodetector Fabricated Using Large Area and Transfer‐Free 2D–2D PtS2/MoS2 Heterostructure

Abstract2D transitional metal dichalcogenide (TMDC) materials have shown great potential in the optoelectronics and electronics field owing to their unique and favorable properties. However, developing high‐performance broadband photodetectors in bare TMDC material is impeded due to their limited absorption and poor charge‐carrier separation. The recent advancement in van der Waals heterostructure fabrication has exhibited a new path to improve the device performance. In the present work, a facile approach is presented to fabricate a large area of PtS2/MoS2 heterostructure, which demonstrates a broad spectral detection range from 400 to 1200 nm with high responsivity (30.2 A W−1) and detectivity (1.12 × 1013 Jones) even under near‐infrared (NIR) 900 nm light illumination at moderate bias. Moreover, the PtS2/MoS2 photodetector exhibits a much enhanced responsivity (97 times) and detectivity (33 times) compared with bare MoS2. A rise/fall time of 11 ms/10 ms for the PtS2/MoS2 device represents its fast response speed. The X‐ray photoelectron spectroscopy measurements reveal the type‐I band alignment between the PtS2 and MoS2, which are further utilized to understand the charge carrier dynamics between the PtS2 and MoS2 interface. This work presents a simple strategy to synthesize scalable, high‐performance broadband photodetectors for future optoelectronics applications.

Synergistic effects of sulphur vacancies and MoS2 on the photocatalytic activity of CdxZn1-xS for H2 evolution

Efficient photocatalysts nurture great potential for harnessing sunlight to produce chemical energy, a pivotal step towards sustainable fuel production. However, designing such systems poses significant challenges due to the complex interaction between light absorption and charge carrier dynamics. In an attempt to address these challenges, this study introduces a novel approach, combining bulk-twinned homojunction CdxZn1-xS photocatalysts with sulphur vacancies. These CdxZn1-xS photocatalysts are seamlessly integrated with molybdenum disulfide (MoS2) to optimize photocatalytic properties and enhance charge transfer via the formation of heterojunctions. Due to its unique crystal structure, the twinned homojunction in CdxZn1-xS enhances light absorption and charge carrier generation. The integrated sulphur vacancies perform several functions: they expediate light adsorption and inhibit electron-hole recombination. These vacancies were initially introduced into the bulk structure during CdxZn1-xS solid solution synthesis. Further, MoS2 provided an augmentation at the surface modification level, thus enhancing their functional role and amplifying their impact on the overall photocatalytic efficiency. The heterojunction formed between MoS2 and CdxZn1-xS provides an integrated efficient platform for overall performance. The composite nanocrystals, wurtzite/zinc-blende twinned MoS2/CdxZn1-xS, were synthesized via an N, N-dimethylformamide-assisted solvothermal method. Detailed characterization was conducted to establish correlations among activity, morphology, and surface properties. The resulting composite photocatalysts demonstrated improved solar hydrogen generation activity and stability, surpassing the performance of twinned crystal CdxZn1-xS.

The Effect of the Mid‐Shell Thickness on the Charge‐Carrier Dynamics of the Green‐Light Emitting InP/ZnSe/ZnS Core‐Shell Quantum Dots

AbstractUltrafast charge carrier dynamics of green‐light emitting InP/ZnSe/ZnS core–shell quantum dots (QDs) with three different ZnSe thickness of 2.0 nm (gQD‐20), 2.4 nm (gQD‐24), or 3.3 nm (gQD‐33) are interrogated by femtosecond transient absorption (TA) and femtosecond stimulated Raman spectroscopy (FSRS). Auger‐type cooling of hot electron into the band‐edge level of InP is clearly manifested in the TA spectra, giving its time constant of ≈222, 300, or 349 fs for gQD‐20, gQD‐24, or gQD‐33, respectively, indicating that the state‐filling to the 1S(e) of InP is significantly slowed down with the increase of the mid shell thickness. The global analysis of the whole TA spectra turns out to be extremely useful to explain the dynamic behavior of the heterogeneous ensemble of single and/or bi‐ (or multi‐) excitons in the presence of the Stark‐shift. The hole‐relaxation dynamics into the band‐edge 1S (h) of the core InP is revealed in the bleaching dynamics of the FSR bands corresponding to the phonon mode of InP or ZnSe, giving the estimated lifetime of 1.0–1.4 ps for gQD‐20. The hole‐relaxation dynamics by the phonon emission seem to be little sensitive to the ZnSe shell thickness.

Investigation of charge-carriers dynamics and sub/super-linear response for La0.8Na0.2-x□xMnO3 (x = 0 and 0.1) perovskite ceramics

La0.8Na0.2-x□xMnO3 (x = 0 and 0.1) compounds were prepared by solid-state reaction. XRD patterns were used to check the structural properties. Experimental results were discussed in terms of different theoretical approaches. The temperature dependence of DC-conductivity displays the presence of a metal-semiconductor transition for x = 0 and 0.1. The introduction of 10%-vacancy provokes a significant increase in the conductivity. The electrical conductivity is explained by many kinds of hopping each one is pronounced in a different temperature region. Two deviation temperatures are observed. These temperatures coincide with the ANC temperatures and the change in the conduction process. For x = 0.1, the Nyquist diagrams shows the presence of a high frequency inductive behavior. AC-conductivity spectra obey to the JPL and DJP. Then, SPL and NCL behaviors appear at high frequency range. The power "s" presents the contribution of numerous conduction models. The scaling behavior reveals that the conductivity spectra obey to the TTS principle.

Single Atom Catalysts for Photoelectrochemical Water Splitting

AbstractSingle atom catalysts (SACs) have attracted increasing attention in electrocatalysis due to their unprecedented catalytic activity with excellent atomic utilization efficiency derived from unique electronic states and coordination environments. In photoelectrochemical (PEC) water splitting, atomically dispersed metal catalysts anchored to photoelectrodes offer the breakthrough to outperform the conventional thin‐film PEC catalysts by enlarging the catalytic sites and facilitating photogenerated charge carrier kinetics. Herein, we present a comprehensive review of SAC‐incorporated photoelectrodes for efficient PEC water splitting. Firstly, the representative characterization techniques for the identification of SACs and investigations in respect of photogenerated charge carrier kinetics and photon‐to‐current efficiency will be discussed. Then, we will introduce the state‐of‐the‐art PEC‐SACs classified into noble metal, non‐noble metal, and dual metal SACs. Finally, critical outlooks to realize the full potential of SACs in photoelectrocatalysis will be highlighted.

The Spacer Cation with Disulfide Bond for Efficient and Stable Low‐Dimensional Dion–Jacobson Perovskite Solar Cells

AbstractLow‐dimensional (LD) perovskite has provided an exciting avenue for exploring stable perovskite solar cells (PSCs). However, PSCs based on LD perovskites still suffer from poor efficiency owing to unfavorable charge carrier dynamics. Here, cystamine (CYS) is employed as a ligand to construct LD Dion‐Jacobson (LDDJ) perovskite (CYS)MAn‐1PbnI3n+1 (n = 1, 2, 3…, MA: methylamine) for improving carrier properties. The disulfide bond not only changes the polarization characteristic but also increases the coupling between inorganic slabs due to the low barrier of rotation around the S‐S axis, thus reducing the exciton binding energy of CYS‐based LDDJ perovskite. Disulfide bonds provide a scene for charge localization in the interlayer region, which is conducive to reducing the anisotropy of charge transfer. Thanks to these merits, the (CYS)MA4Pb5I16 film delivers improved carrier diffusion length (electron for 1345 nm and hole for 950 nm) and mobility (9.23 cm2 V−1 S−1). As a result, the (CYS)(MA)4Pb5I16 PSC achieves a champion power conversion efficiency (PCE) of 16.52%, which is much higher than that of HDA and BA cations‐based PSCs (HDA: 1,6‐Hexanediamine, BA: Butylamine). Furthermore, the state‐of‐the‐art device only lost 8% of its initial PCE after 1600 h in the atmosphere.

Charge carrier dynamics in conducting polymer PEDOT using abinitio molecular dynamics simulations.

As conducting polymers become increasingly important in electronic devices, understanding their charge transport is essential for material and device development. Various semi-empirical approaches have been used to describe temporal charge carrier dynamics in these materials, but there have yet to be any theoretical approaches utilizing abinitio molecular dynamics. In this work, we develop a computational technique based on abinitio Car-Parrinello molecular dynamics to trace charge carrier temporal motion in archetypical conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT). Particularly, we analyze charge dynamics in a single PEDOT chain and in two coupled chains with different degrees of coupling and study the effect of temperature. In our model we first initiate a positively charged polaron (compensated by a negative counterion) at one end of the chain, and subsequently displace the counterion to the other end of the chain and trace polaron dynamics in the system by monitoring bond length alternation in the PEDOT backbone and charge density distribution. We find that at low temperature (T = 1K) the polaron distortion gradually disappears from its initial location and reappears near the new position of the counterion. At the room temperature (T = 300K), we find that the distortions induced by polaron, and atomic vibrations are of the same magnitude, which makes tracking the polaron distortion challenging because it is hidden behind the temperature-induced vibrations. The novel approach developed in this work can be used to study polaron mobility along and between the chains, investigate charge transport in highly doped polymers, and explore other flexible polymers, including n-doped ones.

Manipulating Lone-Pair-Driven Luminescence in 0D Tin Halides by Pressure-Tuned Stereochemical Activity from Static to Dynamic.

The excellent luminescence properties and structural dynamics driven by the stereoactivity of the lone pair in a variety of low-dimensional ns2 metal halides have attracted growing investigations for optoelectronic applications. However, the structural and photophysical aspects of the excited state associated with the lone pair expression are currently open questions. Herein, zero-dimensional Sn-based halides with static stereoactive 5 s2 lone pairs are selected as a model system to understand the correlations between the distinctive lone pair expression and the excited-state structural relaxation and charge carrier dynamics by continuous lattice manipulation. Lattice compression drives 5 s2 lone pair active switching and self-trapped exciton (STE) redistribution by suppressing excited-state structural deformation of the isolated SnBr4 2- units. Our results demonstrate that the static expression of the 5 s2 lone pair results in a red broadband triplet STE emission with a large Stokes shift, while its dynamic expression creates a sky-blue narrowband emission dominated by the radiative recombination of singlet STEs. Our findings and the photophysical mechanism proposed highlight the stereochemical effects of lone pair expression in controlling light emission properties and offer constructive guidelines for tuning the optoelectronic properties in diverse ns2 metal halides.

Manipulating Lone‐Pair‐Driven Luminescence in 0D Tin Halides by Pressure‐Tuned Stereochemical Activity from Static to Dynamic

AbstractThe excellent luminescence properties and structural dynamics driven by the stereoactivity of the lone pair in a variety of low‐dimensional ns2 metal halides have attracted growing investigations for optoelectronic applications. However, the structural and photophysical aspects of the excited state associated with the lone pair expression are currently open questions. Herein, zero‐dimensional Sn‐based halides with static stereoactive 5 s2 lone pairs are selected as a model system to understand the correlations between the distinctive lone pair expression and the excited‐state structural relaxation and charge carrier dynamics by continuous lattice manipulation. Lattice compression drives 5 s2 lone pair active switching and self‐trapped exciton (STE) redistribution by suppressing excited‐state structural deformation of the isolated SnBr42− units. Our results demonstrate that the static expression of the 5 s2 lone pair results in a red broadband triplet STE emission with a large Stokes shift, while its dynamic expression creates a sky‐blue narrowband emission dominated by the radiative recombination of singlet STEs. Our findings and the photophysical mechanism proposed highlight the stereochemical effects of lone pair expression in controlling light emission properties and offer constructive guidelines for tuning the optoelectronic properties in diverse ns2 metal halides.

Pulse-Induced Dynamics of a Charge-Transfer Complex from First Principles.

The ultrafast dynamics of charge carriers in organic donor-acceptor interfaces are of primary importance to understanding the fundamental properties of these systems. In this work, we focus on a charge-transfer complex formed by quaterthiophene p-doped by tetrafluoro-tetracyanoquinodimethane and investigate electron dynamics and vibronic interactions also at finite temperatures by applying a femtosecond pulse in resonance with the two lowest energy excitations of the system with perpendicular and parallel polarization with respect to the interface. The adopted ab initio formalism based on real-time time-dependent density-functional theory coupled to Ehrenfest dynamics enables monitoring the dynamical charge transfer across the interface and assessing the role played by the nuclear motion. Our results show that the strong intermolecular interactions binding the complex already in the ground state influence the dynamics, too. The analysis of the nuclear motion involved in these processes reveals the participation of different vibrational modes depending on the electronic states stimulated by the resonant pulse. Coupled donor-acceptor modes mostly influence the excited state polarized across the interface, while intramolecular vibrations in the donor molecule dominate the excitation in the orthogonal direction. The results obtained at finite temperatures are overall consistent with this picture, although thermal disorder contributes to slightly decreasing interfacial charge transfer.

Influence of an Organic Salt-Based Stabilizing Additive on Charge Carrier Dynamics in Triple Cation Perovskite Solar Cells.

Besides further improvement in the power conversion efficiency (PCE) of perovskite solar cells (PSC), their long-term stability must also be ensured. Additives such as organic cations with halide counter anions are considered promising candidates to address this challenge, conferring both higher performance and increased stability to perovskite-based devices. Here, a stabilizing additive (N,N-dimethylmethyleneiminium chloride, [Dmmim]Cl) is identified, and its effect on charge carrier mobility and lifetime under thermal stress in triple cation perovskite (Cs0.05 MA0.05 FA0.90 PbI3 ) thin films is investigated. To explore the fundamental mechanisms limiting charge carrier mobility, temperature-dependent microwave conductivity measurements are performed. Different mobility behaviors across two temperature regions are revealed, following the power law Tm , indicating two different dominant scattering mechanisms. The low-temperature region is assigned to charge carrier scattering with polar optical phonons, while a strong decrease in mobility at high temperatures is due to dynamic disorder. The results obtained rationalize the improved stability of the [Dmmim]Cl-doped films and devices compared to the undoped reference samples, by limiting temperature-activated mobile ions and retarding degradation of the perovskite film.

Regulating Charge Carrier Dynamics in Stable Perovskite Nanorods for Photo-Induced Atom Transfer Radical Polymerization.

Semiconducting nanocrystals have attracted world-wide research interest in artificial photosynthesis due to their appealing properties and enticing potentials in converting solar energy into valuable chemicals. Compared to 0D nanoparticles, 1D nanorods afford long-distance charge carriers separation and extended charge carriers lifetime due to the release of quantum confinement in axial direction. Herein, stable CsPbBr3 nanorods of distinctive dimensions are crafted without altering their properties and morphology via grafting hydrophobic polystyrene (PS) chains through a post-synthesis ligand exchange process. The resulting PS-capped CsPbBr3 nanorods exhibit a series of enhanced stabilities against UV irradiation, elevated temperature, and polar solvent, making them promising candidates for photo-induced atom transfer radical polymerization (ATRP). Tailoring the surface chemistry and dimension of the PS-capped CsPbBr3 nanorods endows stable, but variable reaction kinetics in the photo-induced ATRP of methyl methacrylate. The trapping-detrapping process of photogenerated charge carriers lead to extended lifetime of charge carriers in lengthened CsPbBr3 nanorods, contributing to a facilitated reaction kinetics of photo-induced ATRP. Therefore, by leveraging such stable PS-capped CsPbBr3 nanorods, the effects of surface chemistry and charge carriers dynamics on its photocatalytic performance are scrutinized, providing fundamental understandings for designing next-generation efficient nanostructured photocatalyst in artificial photosynthesis and solar energy conversion.

Understanding the Charge Carrier Dynamics, Improved Dielectric Properties and Leakage Current Behaviour of NiFe1.85Dy0.15O4 with Structural Correlation

This research explores the charge carrier dynamics of NiFe1.85Dy0.15O4 with excess amounts of Dy ions replacing the metal ions and forming an additional orthorhombic phase of DyFeO3 confirmed by the X-ray diffraction pattern of the sample and validated by Scanning electron microscopy and UV-Visible studies. Dy incorporation, in conjunction with the additional phase, has been shown to alter the structure of the inverse spinel matrix by expanding the unit cell and inducing strain. Impedance spectroscopy was used to investigate the sample’s behaviour as a circuit element, and an equivalent circuit containing resistance, capacitance, and inductance was realized to represent the sample when exposed to an alternating field. The Cole-Cole model of non-Debye relaxation was used to calculate dielectric parameters such as dielectric strength, high-frequency permittivity, shape parameters, and dielectric relaxation times. The specimen’s leakage current conduction mechanism was also systematically investigated to determine the presence of different variants of bulk and interface-limited conduction processes. This multifaceted study not only reveals the intriguing charge dynamics of NiFe1.85Dy0.15O4, which are influenced by Dy-ion incorporation and the emergence of a new phase but also extends its implications to the realm of potential applications, spurring developments in areas like novel energy storage technologies and advanced electronics.

Efficient Photocatalytic CO2 Reduction with High Selectivity for Ethanol by Synergistically Coupled MXene-Ceria and the Charge Carrier Dynamics.

The primary factors that govern the selectivity and efficacy of CO2 photoreduction are the degree of activation of CO2 on the active surface sites of photocatalysts and charge separation/transfer kinetics. In this context, the rational synthesis of heterostructured MXene-coupled CeO2-based photocatalysts with different loading concentrations of Ti3C2MXene via a one-step hydrothermal approach has been undertaken. These photocatalysts exhibit a shift in X-ray diffraction peaks to higher 2θ values and changes in stretching vibrations of 5 wt % Ti3C2MXene/CeO2(5-TC/Ce) that indicate interaction between Ti3C2MXene and CeO2. Moreover, XPS analysis confirms the presence of the Ce3+/Ce4+ states. A sharp band at 2335 cm-1 observed during the CO2 photoreduction process corresponds to bidentate b-CO32-, which facilitates the adsorption of CO2 at the surface of the catalyst as revealed by the TPD analysis. Furthermore, the Schryvers test and NMR analysis were undertaken to confirm the formaldehyde intermediate formation during CO2 photoreduction to C2H5OH. The decrease in emission intensity, reduced lifetimes (2.68 ns), and lower interfacial resistance, as revealed by PL, TR-PL, and EIS analysis, imply an efficient charge separation and charge transfer in the case of the Ti3C2MXene/CeO2 heterojunction. The decrease in the intensity of peaks in the EPR spectrum in the case of 5-TC/Ce further confirms efficient charge transfer kinetics across the interface. The optimized 5-TC/Ce shows CO2 reduction with a drastically enhanced yield of ethanol on the order of 6127 μmol g-1 at 5 h with 98% selectivity and 7.54% apparent quantum efficiency, which is 6-fold higher than that of ethanol produced by bare CeO2. Herein, CeO2 that acts as a redox couple (Ce3+/Ce4+) when coupled with MXene having a metallic nature that reduces the electron transfer resistance is in unison, enabling an enhanced mobilization of electrons. Thereby, the synergistic coupling of Ti3C2MXene with CeO2 leads to an efficient photoreduction of CO2 under visible light illumination.