Hybrid Bulk Heterojunction Solar Cells Research Articles

Incorporation of Gold Nanoparticle into ZnO Electron Transport Layer to Improve Performance of Hybrid Bulk Heterojunction Solar Cell

Abstract We have investigated the effect of localized surface plasmon resonance (LSPR) from gold nanoparticles incorporated into the electron transport layer (ETL) of zinc oxide (ZnO) on charge carrier transport in order to improve the performance of inverted hybrid bulk-heterojunction solar cells. Synthesis of gold nanoparticles capped by 3-mercaptopropionic acid (AuMPA) and oleylamine (AuOA) was carried out by use of the reduction method and the fabrication of solar cell device with the configuration of ITO/ZnO:AuNPs/P3HT:PCBM/PEDOT:PSS/Ag was done by spin coating and thermal evaporation techniques. The absorbance spectra show a plasmonic peak of AuMPA in solution at 521 nm, while AuOA has a plasmonic peak at 531 nm, with both solutions showing a red-wine color. In our investigation, the incorporation of AuMPA about 2.65wt% or AuOA about 3.5 wt% in the ZnAc solution is quite stable. With the addition of 1.77 wt% AuMPA, the fabricated devices show a significant improvement at short circuit condition (JSC) from 46.67 mA/cm2 to 83.11 mA/cm2, resulting in an increase in power conversion efficiency (PCE) from 5.64% to 9.00% under the illumination of 100 mW/cm2 simulated solar irradiation. While the AuOA addition of 2.65 wt%, the JSC increased from 22.67 mA/cm2 to 44.12 mA/cm2 along with an improvement of PCE from 2.71% to 5.32%. The experiment results suggest that the electron mobility or charge carrier transport to the indium tin oxide (ITO) cathode is improved by the local electric field enhancement around the zinc oxide (ZnO) electron transport layer due to the effect of gold nanoparticles (AuNPs).

An inverted architecture P3HT:CdSe bulk-heterojunction hybrid solar cell utilizing a quantum junction with high open circuit voltage and efficiency

Exploring CdSe QDs as a substitute for [6,6]-phenyl-C61 butyric acid methyl ester (PCBM) in Poly (3-hexylthiophene) (P3HT) based photovoltaic devices received much attention due to its properties such as tunable band gap over the visible range, better band alignment with P3HT and inexpensiveness. But, the VOC values of the P3HT:CdSe QDs bulk-heterojunction (BHJ) hybrid solar cells are still inferior, which happens to be the main performance-limiting factor for these devices. We have resolved this issue in this study by the application of an interfacial buffer layer (BL) in an inverted architecture utilizing zinc oxide (ZnO) as an electron transporting layer. The BL was also formed of CdSe QDs. It was found that the application of the interfacial BL reduces the interface recombination which resulted in a VOC value of 0.96 V. To the best of our knowledge, this is the best VOC value reported for the P3HT:CdSe QDs BHJ system so far. A quantum junction (QJ) was also formed between the QDs in the BL and the QDs in the BHJ by passivating them with Iodine and 3-Mercaptopropionic acid (MPA), respectively. The QJ induces an extended electric field in the BHJ which benefits charge extraction and ultimately resulting in an enhanced short circuit current (JSC).

Selected organic dyes (carminic acid, pyrocatechol violet and dithizone) sensitized metal (silver, neodymium) doped TiO2/ZnO nanostructured materials: A photoanode for hybrid bulk heterojunction solar cells

A photoactive nanohybrid material consisting of pyrocatechol violet, carminic acid and dithizone dyes functionalized silver and neodymium-doped TiO2/ZnO nanostructured materials is reported here, as photoactive blend, for solid-state dye sensitized solar cell. First of all we synthesized metals (silver, neodymium) doped (TiO2) Titanium oxide nanoparticles and their nanocomposites (TiO2/ZnO, M−TiO2/ZnO) using the sol–gel and reflux technique, respectively. The synthesized samples were then characterized by UV–Visible spectroscopy, X-Ray diffraction Analysis (XRD), Scanning electron microscopy (SEM), Energy dispersive X-Ray Analysis (EDX), and Fourier Transform infrared spectroscopy (FTIR). Optical studies were done through UV–Visible spectroscopy and the absorption spectra were used to calculate band gaps. The value of the energy gap for TiO2 nanoparticles is 3.10 eV which was gradually tuned to 2.47 eV after incorporating metals (Ag and Nd) and forming respective nanocomposites. X-Ray diffraction Analysis (XRD) patterns revealed the purity and crystallinity in samples. Scanning electron microscopy (SEM) confirmed the irregular morphology (nanorods and spherical shaped) of ZnO and TiO2 nanostructures respectively. The elemental composition of nanomaterials was successfully investigated using energy dispersive X-ray analysis (EDX). In the absence of any impurities, Fourier Transform infrared spectroscopy (FTIR) was used to identify the functional groups in synthesized material. For device fabrication, a solid-state electrolyte, P3HT, a hole conducting polymer was used. Characterization of fabricated solar cells was done using I-V measurements. Under simulated solar irradiation, the DSSC based on pyrocatechol violet sensitized neodymium doped TiO2/ZnO nanohybrid materials exhibited the best PCE (power conversion efficiency) of 2.38 % and significantly improved Jsc (short circuit current density) of 15.68 mA/cm2 as compared to carminic acid and dithizone in photovoltaic measurements. The improved power conversion efficiency of this device is ascribed to the particle size, increased dye adsorption, increased surface area and thus improved short circuit current density (Jsc).

Synthesis of Cu-doped ZnO for bulk heterojunction hybrid solar cells

Synthesis of Cu-doped ZnO for bulk heterojunction hybrid solar cells

Morphology Control of Monomer-Polymer Hybrid Electron Acceptor for Bulk-Heterojunction Solar Cell Based on P3HT and Ti-Alkoxide with Ladder Polymer.

We report the morphology control of a nano-phase-separated structure in the photoactive layer (power generation layer) of organic–inorganic hybrid thin-film solar cells to develop highly functional electronic devices for societal applications. Organic and inorganic–organic hybrid bulk heterojunction solar cells offer several advantages, including low manufacturing costs, light weight, mechanical flexibility, and a potential to be recycled because they can be fabricated by coating them on substrates, such as films. In this study, by incorporating the carrier manager ladder polymer BBL as the third component in a conventional two-component power generation layer consisting of P3HT—the conventional polythiophene derivative and titanium alkoxide—we demonstrate that the phase-separated structure of bulk heterojunction solar cells can be controlled. Accordingly, we developed a discontinuous phase-separated structure suitable for charge transport, obtaining an energy conversion efficiency higher than that of the conventional two-component power generation layer. Titanium alkoxide is an electron acceptor and absorbs light with a wavelength lower than 500 nm. It is highly sensitive to LED light sources, including those used in homes and offices. A conversion efficiency of 4.02% under a 1000 lx LED light source was achieved. Hence, high-performance organic–inorganic hybrid bulk heterojunction solar cells with this three-component system can be used in indoor photovoltaic systems.

Defect mediated improved charge carrier dynamics in hybrid bulk-heterojunction solar cell induced by phase pure iron pyrite nanocubes

In this article, the synthesis of phase pure iron pyrite nanocubes (FeS2 NCs) and their various effects on the charge carrier dynamics and photovoltaic performances of P3HT:PC71BM based hybrid bulk-heterojunction solar cells have been studied. The optimum doping concentration of FeS2 NCs was found to be 0.3 wt%. For the optimally doped devices, the short-circuit current density was found to have improved from 5.47 to 7.99 mA cm−2 leading to an overall cell efficiency improvement from 2.10% to 3.22% as compared to the undoped reference devices. The enhancement in photovoltaic performance is mainly attributed to the formation of localized energy states near the band edges leading to higher carrier generation rate by 72% whereas carrier dissociation probability is also increased by 13%. Urbach energy estimation reveals that the optimally doped devices have achieved a relatively balanced amount of localized states resulting in reduced non-radiative recombination. Such localized defect states formation with FeS2 NCs doping was also found to have significant influence over the charge carrier dynamics of the active layer. Transient photocurrent and photovoltage studies revealed that FeS2 NCs assist in faster carrier extraction by reducing the transport time from 1.4 to 0.6 μs and by enhancing carrier recombination time from 51.7 to 78.9 μs for the reference and optimum devices respectively. Such an unorthodox approach of defect state assisted efficiency improvement demonstrates the importance of simultaneously understanding the charge carrier dynamics and photovoltaic performance for rational device optimization, and opens new prospects for developing high-efficiency solution processable hybrid devices.

Mesoscale Simulations on Morphology Design in Conjugated Polymers and Inorganic Nanoparticles Composite for Bulk Heterojunction Solar Cells

Mixtures of conjugated polymers (CPs) as donors and inorganic semiconducting nanoparticles (NPs) as acceptors are considered to be promising materials for photoactive layers of bulk heterojunction hybrid solar cells (HSCs). To reach the high power conversion efficiency of HSC, the morphology of the photoactive layer for providing optimal charge transport paths is designed. Herein, the coarse‐grained model for predicting the morphology of nanocomposites based on semiconducting CPs and NPs is used. For polymer matrix, well‐known CPs such as poly(3‐hexythiophene) (P3HT), poly [thieno [3,4‐b] thiophene/benzodithiophen] (PTB7), and poly [[2,6′‐4,8‐ di(5‐ethylhexylthienyl)benzo[1,2‐b;3,3‐b] dithiophene][3‐fluoro‐ 2[(2‐ethylhexyl) carbonyl] thieno[3,4‐b]thiophenediyl]] (PTB7‐Th) are selected. For NP fillers, PbS quantum dots modified by ligands (like, e.g., oleic acid) are selected. Via mesoscale computer simulations, it is shown that by choosing appropriate ligands for NPs and varying the weight fraction of NPs, the morphology with bicontinuous charge transport paths for holes and electrons is obtained. Such morphologies are observed in models of homopolymer/NP blends for the first time. This finding is in reasonable agreement with the recent experimental results on these systems.

Photovoltaic Characterization of Hybrid Bulk Heterojunction Solar Cell Incorporated Gold Nanoparticles Embedded in Active Layer

We attempt to study the effect of gold nanoparticles embedded into the active polymer of regioreguler poly (3-hexylthiophene) (P3HT) and phenyl-C61-butyric acid methyl ester (PCBM) on the charge kinetic to enhance the performance of bulk-heterojunction solar cell. It has been known that the generation of localized surface plasmon resonance (LSPR) would both increase the photon absorption and improve the efficiency of charge separation. Synthesis of gold nanoparticles stabilized by oleylamine (AuOA) was carried out by reduction method and resulted in the spherical shape of nanoparticles with a diameter size of ~12 nm. The absorbance spectra show the typical of surface plasmon peak of AuOA in solution at ~527 nm. Fabrication of inverted bulk-heterojunction solar cell device was done in the configuration of ITO/ZnO/P3HT:PCBM:AuOA/PEDOT:PSS/Ag. Incorporation of AuOA in polymer solution is clearly detected from the enhanced absorbance peak resulted from UV-Vis measurement and the mix solution of P3HT:PCBM:AuOA is quite stable in the concentration of AuOA less than 10 wt%. In our experiment, fabricated solar cell reveals the enhancement in current density at short circuit condition (Jsc) from 44.57 mA/cm2 to 56.14 mA/cm2 with the addition of 3.9 wt% AuOA in polymer solution along with the enhancement of power conversion efficiency (PCE) from 4.07% to 6.23% as characterized by J-V measurement. In our case, the voltage at open circuit condition (Voc) of the device does not show significant improvement.

Plasma treatment of zinc oxide‐nanoparticles:polyaniline blend as an active layer for the hybrid bulk heterojunction solar cell applications

Plasma treatment of zinc oxide‐nanoparticles:polyaniline blend as an active layer for the hybrid bulk heterojunction solar cell applications

Utility of copper oxide nanoparticles (CuO-NPs) as efficient electron donor material in bulk-heterojunction solar cells with enhanced power conversion efficiency

Abstract In the present work, we have endeavored the utilization of wet-chemically synthesized copper oxide nanoparticles (CuO-NPs) as the active layer in hybrid bulk heterojunction (BHJ) solar cells. The BHJs with CuO-NPs display significantly different physics from customary BHJs, and prove a noteworthy improvement in their performance. It is noted that with the addition of CuO-NPs, the morphology of the photoactive layer endures significant changes. Incorporating CuO-NPs is an additional paradigm for BHJs solar cells which enhances the photocurrent density from 9.43 mA/cm2 to 11.32 mA/cm2 and the external quantum efficiency as well. Also the power-conversion efficiency (PCE) improved from 2.85% to 3.82% without harming the open circuit voltage and the fill factor. The enhancement in PCE achieved here makes it worthy to design high-performance organic solar cells holding inorganic nanoparticles.

An inverted ZnO/P3HT:PbS bulk-heterojunction hybrid solar cell with a CdSe quantum dot interface buffer layer.

An inverted bulk-heterojunction (BHJ) hybrid solar cell having the structure ITO/ZnO/P3HT:PbS/Au was prepared under ambient conditions and the device performance was further enhanced by inserting an interface buffer layer of CdSe quantum dots (QDs) between the ZnO and the P3HT:PbS BHJ active layer. The device performance was optimized by controlling the size of the CdSe QDs and the buffer layer thickness. The buffer layer, with an optimum thickness and QD size, has been found to promote charge extraction and reduces interface recombinations, leading to an increased open-circuit voltage (VOC), short circuit current density (JSC), fill factor (FF) and power conversion efficiency (PCE). About 40% increase in PCE from 1.7% to 2.4% was achieved by the introduction of the CdSe QD buffer layer, whose major contribution comes from a 20% increase of VOC.

Comparative Charge Transport Study of MEHPPV–TiO2 and P3HT–TiO2 Nanocomposites for Hybrid Bulk Heterojunction Solar Cells

TiO₂ nanorods integrated with poly[2-methoxy,5-(2-ethylhexyloxy)-p-phenylenevinylene] (MEHPPV) and poly(3-hexylthiophene) (P3HT) matrixes were investigated for charge transport properties to evaluate their potential application in a hybrid solar cell device. An exhaustive characterization was performed to identify the best hybrid nanocomposite among MEHPPV-TiO₂ and P3HT-TiO₂. The analysis involved optical and electrical characterization techniques such as the X-ray diffraction, field emission scanning electron microscope, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, photoluminescence, atomic force microscopy, X-ray photoelectron spectroscopy, and I-V measurements. TiO₂ nanorods exhibited excellent dispersion in both polymer matrixes, thus significantly improving the photocurrent generation and net efficiency. Therefore, the overall device performance was improved. The findings of this study demonstrated that the P3HT-TiO₂ photovoltaic device exhibited superior performance than the MEHPPV-TiO₂ photovoltaic device. We believe that this evaluation would certainly contribute to the understanding of interfacial exciton dissociation in nanoscale morphology for the next-generation hybrid bulk heterojunction solar cells.

Synthesis and characterization of transition metals doped CuO nanostructure and their application in hybrid bulk heterojunction solar cells

Herein, transition metals i.e. Mn, Fe doped CuO nanostructures were synthesized via simple and facile wet chemical method. As-prepared materials were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscope (TEM), ultraviolet–visible and emission spectroscopy. The XRD studies reveal that doped and un-doped CuO have single phase, suggesting the incorporation of Mn and Fe dopants in CuO lattice. Further, as-synthesized materials were used in the hybrid bulk heterojunction organic solar cell and it was found that the low concentration of doping increase the charge separation led to enhance the power conversion efficiency of the device as compared to high amount of doping. This increase in the power conversion efficiency of the prepared devices is mostly due to increase in fill factor and short-circuit current density upon doping of Mn:Fe to CuO nanostructures.

Enhanced Device Performance of Bulk Heterojunction (BHJ) Hybrid Solar Cells Based on Colloidal CdSe Quantum Dots (QDs) via Optimized Hexanoic Acid-Assisted Washing Treatment

As-synthesized colloidal quantum dots (QDs) are usually covered by an organic capping ligand. These ligands provide colloidal stability by preventing QDs agglomeration. However, their inherent electrical insulation properties deliver a problem for hybrid solar cell application, disrupting charge transfer, and electron transport in conjugated polymer/QDs photoactive blends. Therefore, a surface modification of QDs is crucial before QDs are integrated into solar cell fabrication. In this work, enhancement of power conversion efficiency (PCE) in bulk heterojunction (BHJ) hybrid solar cells based on hexadecylamine- (HDA-) capped CdSe quantum dots (QDs) has been achieved via a postsynthetic hexanoic acid washing treatment. The investigation of the surface modification was performed to find the optimum of washing time and their effect on solar cell devices performance. Variation of washing time between 16 and 30 min has been conducted, and an optimum washing time was found at 22 min, resulting in a high PCE of 2.81%. The efficiency enhancement indicates improved electron transport, contributing in an increased short-circuit current density of solar cell devices.

Improved Hole Injection in Bulk Heterojunction (BHJ) Hybrid Solar Cells by Applying a Thermally Reduced Graphene Oxide Buffer Layer

In this work, the utilization of graphene oxide (GO), reduced graphene oxide (rGO), and carbon nanotube (CNT) thin films as hole transport and electron-blocking layers in polymer/nanocrystal hybrid solar cells is demonstrated. A simple method has been used to modify the anode of hybrid solar cells by depositing these two solution-processable nanocarbon materials between poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) and transparent indium tin oxide (ITO) layers. Upon the use of an rGO interlayer, we found a substantial improvement in power conversion efficiency (PCE) from 2.5% to 3.2% due to a decrease in series resistance (Rs). This decrease has been obtained by a careful tuning of the reduction degree of rGO, inducing optimization of the energy band alignment at the solar cell anode. In addition, charge extraction by linearly increasing voltage (CELIV) measurements show an increase in light-induced charge extraction of ca. 50%. Finally, the utilization of rGO as replacement for PEDOT:PSS is also presented. The findings reported in this work demonstrate the excellent potential of rGO as an efficient hole transport material in hybrid solar cells.

Morphology Tuning of ZnO/P3HT/P3HT- b-PEO Hybrid Films Deposited via Spray or Spin Coating.

Hybrid films of zinc oxide (ZnO) and poly(3-hexylthiophen-2,5-diyl) (P3HT) show promising characteristics for application in hybrid bulk-heterojunction solar cells (HBSCs). However, the incompatibility of ZnO and P3HT may lead to a reduced interface area, thus reducing the probability of exciton separation and consequently lowering solar cell efficiencies. Here, a diblock copolymer P3HT- b-poly(ethylene oxide) (PEO) is introduced to improve the interface between ZnO and P3HT. ZnO is synthesized via a block copolymer assisted sol-gel approach, and the used zinc precursor is directly incorporated into the PEO blocks. Thus, the possibility of aggregation is reduced for both the inorganic and the organic components, and a good intermixing is ascertained. Two deposition methods, namely, spray and spin coating, are compared with respect to the resulting film structure, which is investigated with scanning electron microscopy and time-of-flight grazing-incidence small-angle neutron scattering measurements. Both the surface and inner morphologies reveal that the spin coated samples possess smaller and less diverse domain sizes than the sprayed films. Due to the advantage of spray coating in large-scale production, the morphology of the sprayed samples is tailored more meticulously by changing the weight fraction of ZnO in the films. The sprayed hybrid films show smaller domains and less aggregation with decreasing the amount of ZnO. This reveals that both the deposition method and composition of the ZnO/P3HT/P3HT- b-PEO hybrid films play an important role for tailoring the film morphology and thus for improving the performance of HBSCs in future application.

Band gap tuning and applications of ZnO nanorods in hybrid solar cell: Ag-doped verses Nd-doped ZnO nanorods

ZnO nanorods doped with different concentrations of Ag and Nd (1–7%) were synthesized by hydrothermal method. In this article we describe the synthesis, characterization and applications of pristine ZnO, Ag-doped ZnO and Nd-doped ZnO nanorods in hybrid bulk heterojunction solar cells. Their optical, structural, and morphological properties were analyzed by using UV–Visible spectroscopy, X-ray diffraction (XRD), Scanning electron microscopy (SEM), and Energy dispersive X-ray spectroscopy (EDX). The X-ray diffraction analysis reveals that the pristine and doped ZnO nanorods were crystallized in a hexagonal wurtzite structure. SEM images supplemented with EDX were used to explore the morphology, size and chemical composition of pristine ZnO, Ag-doped ZnO and Nd-doped ZnO samples. UV visible absorption spectra showed that bathochromic shift occurred when ZnO nanorods were doped with Ag and Nd up to a certain limit of dopant concentration. Doped ZnO nanorods were found more conducting than prisitne ZnO nanorods. This work also represents the chemical modification of pristine ZnO, Ag-doped ZnO, and Nd-doped ZnO nanorods with a bromopyrogallol red dye (Br-PGR) which is not reported yet. The pristine and doped samples were sensitized with Br-PGR and the material so sensitized was tested in solar cell. The optical properties of grafted samples were thoroughly studied by using UV–visible spectroscopy. The Nano-hybrid material was tested as a photoactive blend of the DSSCs and their current-voltage measurements (I-V) were performed to examine the effect of pristine and doped ZnO nanorods on the performance of solar cells. Moreover current voltage (I-V) measurements confirmed the boosting of efficiency in pristine and doped ZnO nanorods based DSSCs owing to their sensitization with Br-PGR. Maximum power conversion efficiency of 1% was recorded for Ag-doped ZnO nanorods.

Integration of Multiwalled Carbon Nanotubes in Bulk Heterojunction CdSe/PCPDTBT Hybrid Solar Cells

In this work, the development of solution-processed bulk heterojunction hybrid solar cells based on CdSe quantum dot (QD) and conjugated polymer poly [2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta [2,1-b;3,4-b] dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)], PCPDTBT was performed. The photoactive layer was formed by integrating CdSe QDs onto multiwalled carbon nanotubes (CNTs). A simple method of thiol functionalization in the interface CNTs and CdSe QDs has been investigated. Integration of CNTs enhances long-term performance of solar cells devices. Initial PCE values of about 1.9 % under AM1.5G illumination have been achieved for this hybrid CNT-CdSe photovoltaic device. In addition, the long-term stability of the photovoltaic performance of the devices was investigated and found superior to CdSe QD only based devices. About 84 % of the initial PCE remained after storage in a glove box for one year without any further encapsulation. It is concluded that the improvement is mainly due to a strong binding between thiol functionalized CNTs and CdSe QDs, resulting preservation of the nanomorphology of the hybrid film over time.

All-conjugated amphiphilic diblock copolymers for improving morphology and thermal stability of polymer/nanocrystals hybrid solar cells

Herein, the ability to optimize the morphology and photovoltaic performance of poly(3-hexylthiophene) (P3HT)/ZnO hybrid bulk-heterojunction solar cells via introducing all-conjugated amphiphilic P3HT-based block copolymer (BCP), poly(3-hexylthiophene)-block-poly(3-triethylene glycol-thiophene) (P3HT-b-P3TEGT), as polymeric additives is demonstrated. The results show that the addition of P3HT-b-P3TEGT additives can effectively improve the compatibility between P3HT and ZnO nanocrystals, increase the crystalline and ordered packing of P3HT chains, and form optimized hybrid nanomorphology with stable and intimate hybrid interface. The improvement is ascribed to the P3HT-b-P3TEGT at the P3HT/ZnO interface that has strong coordination interactions between the TEG side chains and the polar surface of ZnO nanoparticles. All of these are favor of the efficient exciton dissociation, charge separation and transport, thereby, contributing to the improvement of the efficiency and thermal stability of solar cells. These observations indicate that introducing all-conjugated amphiphilic BCP additives can be a promising and effective protocol for high-performance hybrid solar cells.

Overcoming the efficiency limitations of SnS2 nanoparticle-based bulk heterojunction solar cells

This study examined the effects of heat treatment, the electron transport layer, and [6,6]-phenyl C61 butyric acid methyl ester (PCBM) incorporation on the performance of hybrid bulk heterojunction (BHJ) solar cells composed of tin disulfide (SnS2) nanoparticles (NPs) and low band gap energy polymers poly[2,6-(4,4-bis(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b′]dithiophene)-alt-4,7(2,1,3-benzothiadiazole)] (PCPDTBT) or poly({4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl}{3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl}) (PBT7). Inserting an electron transport layer (ETL) (i.e., ZnO) on the top of the photoactive layer improved the surface morphology of the photoactive layer, which led to an improvement in charge transport. Moreover, adding a suitable amount of PCBM to the SnS2/polymer active layer enhanced the device performance, such as short circuit current density (Jsc) and power conversion efficiency (PCE). In particular, adding 0.5 mg of PCBM to the composite solution led to a 25% and 1.5% improvement in the Jsc value and PCE, respectively. The enhanced performance was due mainly to the improvements in the surface morphology of the photoactive layer, charge carrier mobility within the donor–acceptor interface, and carrier collection efficiency at the cathode.