Kesan suhu rendaman dan suhu sepuh lindap dalam penyediaan filem nipis bismut sulfida (bi2s3) terhadap prestasi sel suria organik jenis songsang berasaskan P3HT: PCBM

Filem nipis bismut sulfida (Bi2S3) mempunyai jurang tenaga yang kecil dan boleh dihasilkan dengan mudah pada suhu yang rendah melalui proses pemendapan celupan kimia. Ia adalah bahan yang sesuai untuk digunakan sebagai lapisan pengangkut elektron (ETL) dalam sel suria organik jenis songsang (I-OSC) yang menggantikan zink oksida (ZnO) yang mempunyai jurang jalur tenaga yang besar dan memerlukan suhu sepuh lindap yang tinggi dalam proses penghasilan sel suria berprestasi tinggi. Kajian terdahulu mengenai kesan tempoh rendaman menunjukkan bahawa kecekapan penukaran kuasa (PCE) optimum yang dapat dicapai oleh filem nipis Bi2S3 adalah sehingga 2.32% dengan rendaman selama 30 minit dalam larutan Bi2S3 pada suhu bilik. Dalam kajian ini, suhu rendaman dan sepuh lindap pada penyediaan filem nipis Bi2S3 pula dikaji untuk memerhatikan kesannya terhadap prestasi fotovoltaik I-OSC. Masa rendaman substrat dalam larutan Bi2S3 ditetapkan pada tempoh 30 minit tetapi suhu rendaman dibezakan. Hasil kajian menunjukkan suhu rendaman pada suhu bilik masih memberikan PCE tertinggi iaitu 1.79% dengan nilai ketumpatan arus litar pintas (Jsc,), 8.01 mA.cm-2 dan voltan litar terbuka (Voc), 0.54 V. Selain itu, bagi suhu sepuh lindap, PCE menurun apabila suhu sepuh lindap yang tinggi dikenakan. Menariknya, apabila suhu sepuh lindap yang tinggi digunakan, kehabluran Bi2S3 bertambah baik, tetapi permukaan FTO lebih banyak terdedah kepada P3HT, mengakibatkan kebocoran arus yang tinggi. Kajian ini menunjukkan bahawa sampel yang disediakan pada suhu rendaman dan sepuh lindap yang tinggi tidak menghasilkan prestasi fotovoltaik yang lebih baik

Effect of heat treatment on photoelectrochemical performance of hydrothermally synthesised Ag2S/ZnO nanorods arrays

Low temperature hydrothermal method was used to produce a large surface area ZnO NRs on conductive glass. The same method was used to fabricate a photoelectrode of Ag2S quantum dots onto the nanorod arrays. Ag2S QDs/ZnO NRAs heterostructure was employed as photoanode in a standard 3-electrodes photoelectrochemical cell. A significant enhancement in the photoelectrochemical performance was observed for the Ag2S QDs/ZnO upon heat treatment 400 °C which displayed an impressive photoconversion efficiency of 4.08% by achieving ∼10-times higher compared to bare ZnO NRAs. This enhancement was attributed to the improved morphological structure, crystallinity and optical properties of the synthesised heterostructures

Preparation and characterization of ZnO/ZnAl₂O₄-mixed metal oxides for dye-sensitized photodetector using Zn/Al-layered double hydroxide as precursor

In this article, a simple new technique has been developed for the preparation of ZnO/ZnAl₂O₄-mixed metal oxide (MMO) as anode materials for visible light dye-sensitized (DS) photodetector using Zn/Al-layered double hydroxide (LDH) as precursor. Subsequently, a detailed correlation between the structural properties of the prepared samples and the photo-responsive behavior of the fabricated DS photodetectors was elucidated. Specifically, it is evidenced that a high surface area of the prepared mesoporous MMO anode materials exhibit excellent dye absorptivity and thus facilitate free electron transfer and increase the photocurrent in the fabricated DS photodetector. A significant bathochromic shift was observed in the optical energy of the prepared MMO samples under the increment of molar ratio, providing a short electron transfer pathway in the optimized Z7A DS photodetector, which in turn demonstrated photo-responsivity and photo-detectivity of 6 mA/W and 1.7 × 10⁺¹⁰ Jones, respectively. This work presents an alternative approach for the design of an eco-friendly MMO-based DS photodetector

Surface engineering of ZnO nanorod for inverted organic solar cell

Crystallinity and band offset alignment of inorganic electron acceptor play a vital role in enhancing the device performance of inverted organic solar cell (IOSC). In this report, homogenous and vertically-aligned chemical treated ZnO nanorods (ZNR) were successfully grown on fluorine-doped tin oxide (FTO) substrate via a fully-solution method. It was found that the morphology of ZnO was fine-tuned from truncated surface to tubular structure under both of the anionic (KOH) and protonic (HCl) treatment. An extraordinary defect quenching phenomenon and hyperchromic energy band edge shift were observed in 0.1 M KOH-treated ZNR proven by the highest (0 0 2) peak detection and the lowest defect density. Compared with the pristine sample, the 0.1 M KOH-treated ZNR device showed a remarkable improvement in power conversion efficiency (PCE) up to 0.32%, signifying the effectiveness of anodic treatment. The robust correlation between the dependency of chemical treated ZNR and the device performance was established. This work elucidates a feasible method towards efficient IOSC devices development

Photophysical properties and energy transfer mechanism in PFO/TiO2 /MEH-PPV nanocomposite thin films

Improvement in photophysical properties of poly-9,9-dioctylfluorene (PFO)/10 wt. % TiO2 nanoparticle thin film as a result of systematic additions of poly(2-methoxy-5(2-ethylhexyl)-1,4-phenylenevinylene (MEH-PPV) were investigated. The nanocomposite blends were prepared with additions of MEH-PPV up to 3.0 wt. % of the total weight. All blends were prepared using the solution blending method and subsequently spin-coated onto glass substrates. The UV-Vis absorption and photoluminescence characterizations showed the intensification of the primary-color emissions of the thin films with the Förster resonance as the primary energy transfer mechanism from PFO to MEH-PPV. Important photophysical parameters, such as the Förster radius (Ro ) excited state lifetime (τ), fluorescence quantum yield of the donor (φ), quenching constant (ksv), quenching rate constant (kq ), distance between the donor and acceptor (R), energy transfer lifetime (τET), and energy transfer rate (kET) display better values with increasing the contents of MEH-PPV by 2.5 wt. %, suggesting an ordered improvement on the photophysical properties of the thin film. Finally, a possible underlying mechanism describing the enhancement of the photophysical properties was proposed

Numerical analysis with experimental verification to predict outdoor power conversion efficiency of inverted organic solar devices

Inverted organic solar cell (IOSC) devices with different volume ratios of In₂S₃ nanoparticles have been studied under local spectral irradiances in Malaysia with respect to that of AM1.5G. The J-V curves of encapsulated IOSC devices were measured outdoor using an Ivium Potentiostat and local spectral irradiances were acquired using an AVANTES spectrometer concurrently. All of the IOSC devices experienced significant improvement in power conversion efficiency (PCE) under the both local sunny and cloudy conditions with respect to the AM 1.5G, by 22–35% and 31–65%, respectively. From spectral analysis, the area under the graph of spectral irradiance in UV–visible region is significantly higher compared to infrared region for both local sunny and cloudy conditions, by 44.6% and 55.9%, respectively, while it is only recorded as 12.9% for AM 1.5G. Last but not the least, we have successfully verified the numerical analysis to predict device performance by comparing the simulated and measured PCE values for different irradiance intensities whereby the prediction of PCE is better under sunny condition with a deviation of 3.4–10.8% compared to cloudy conditions, with deviation of 28.9–30.5%

Enhanced photovoltaic performance of CdS-sensitized inverted organic solar cells prepared via a successive ionic layer adsorption and reaction method

One-dimensional ZnO nanorods (ZNRs) synthesized on fluorine-doped tin oxide (FTO) glass by hydrothermal method were modified with cadmium sulfide quantum dots (CdS QDs) as an electron transport layer (ETL) in order to enhance the photovoltaic performance of inverted organic solar cell (IOSC). In present study, CdS QDs were deposited on ZNRs using a Successive Ionic Layer Adsorption and Reaction method (SILAR) method. In typical procedures, IOSCs were fabricated by spin-coating the P3HT:PC61BM photoactive layer onto the as-prepared ZNRs/CdS QDs. The results of current-voltage (I-V) measurement under illumination shows that the FTO/ZNRs/CdS QDs/ P3HT:PC61BM/ PEDOT: PSS/Ag IOSC achieved a higher power conversion efficiency (4.06 %) in comparison to FTO/ZNRs/P3HT:PC61BM/PEDOT: PSS/Ag (3.6 %). Our findings suggest that the improved open circuit voltage (Voc) and short circuit current density (Jsc) of ZNRs/CdS QDs devices could be attributed to enhanced electron selectivity and reduced interfacial charge carrier recombination between ZNRs and P3HT:PC61BM after the deposition of CdS QDs. The CdS QDs sensitized ZNRs reported herein exhibit great potential for advanced optoelectronic application

Silver nanowires as flexible transparent electrode: role of PVP chain length

In this project, crystalline silver nanowires (AgNWs) are successfully grown using a continuous segmented flow process. The robust relationship among the structural, electrical and optical properties of the AgNWs in the function of the polyvinylpyrrolidone (PVP) chain length is elaborated. A concise carrier transport and a density mechanism are also discussed using a localized conductive atomic force microscopy analysis. The obtained results proved that the AgNWs synthesized using PVP with a chain length of 1.3 M exhibit excellent electrical and optical properties in the form of flexible transparent film with a sheet resistance of 90% at various bending angles. These findings present an alternative approach for production of AgNWs and fabrication of a high flexible transparent electrode

Synergy study on charge transport dynamics in hybrid organic solar cell: photocurrent mapping and performance analysis under local spectrum

Charge transport dynamics in ZnO based inverted organic solar cell (IOSC) has been characterized with transient photocurrent spectroscopy and localised photocurrent mapping-atomic force microscopy. The value of maximum exciton generation rate was found to vary from 2.6 × 1027 m−3s−1 (Jsat = 79.7 A m−2) to 2.9 × 1027 m−3s−1 (Jsat = 90.8 A m−2) for devices with power conversion efficiency ranging from 2.03 to 2.51%. These results suggest that nanorods served as an excellent electron transporting layer that provides efficient charge transport and enhances IOSC device performance. The photovoltaic performance of OSCs with various growth times of ZnO nanorods have been analysed for a comparison between AM1.5G spectrum and local solar spectrum. The simulated PCE of all devices operating under local spectrum exhibited extensive improvement with the gain of 13.3–13.7% in which the ZnO nanorods grown at 15 min possess the highest PCE under local solar with the value of 2.82%