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Hierarchical one-dimensional CdS nanowires (NWs)/CdSe core–shell heterostructure have been synthesized through a simple wet chemical approach. The formation of CdS NWs/CdSe core–shell has been confirmed by structural, morphological and optical analysis. Fascinatingly, an optimum number of CdSe nanoparticles loaded over CdS NWs boosts the device efficiency five times than a bare CdS NW structure. The effect of increasing the CdSe SILAR cycles over CdS induces red shift in the absorption wavelength along with quenching, which leads to the negative shift of the conduction band, and hence, increases the electron lifetime, as analyzed by photoluminescence, external quantum efficiency and Mott–Schottky studies. Interestingly, a discrepancy has been found in the device performance with an increase in the SILAR cycles beyond the optimum condition. The reason behind this fact has been investigated through different comprehensive photoelectrochemical characterization and discussed herein. [ABSTRACT FROM AUTHOR]

A bottom-up approach is demonstrated for the synthesis of cadmium sulfide (CdS) nanowires on pregrown compact CdS layer through simple and low cost wet chemical approach. These CdS nanowires are loaded with Ru-metal free organic dyes namely, Rhodamine B and Rose Bengal to serve as a photoanode in dye sensitized solar cells. The dye loaded CdS NWs films revealed good absorption coverage in the visible region of the solar spectrum. The photovoltaic performance of the devices with CdS nanowires shows efficiency of 0.1201% ± 6.6 × 10 −5 % for Rhodamine B and 0.125% ± 3.4 × 10 −5 % for Rose Bengal dye under standard illumination of sunlight (AM 1.5 G, 100 mW/cm 2 ). The use of 1-D CdS nanowire proves well directed electron pathway which may exhibit promising candidate towards the next generation colourful solar cell. [ABSTRACT FROM AUTHOR]

• First report on core-shell heterostructure between CdS nanowires (NWs) and Bi 2 Se 3 nanoparticles. • State of art to use of simple and low-cost chemical route to decorate Bi 2 Se 3 nanoparticles on high surface area CdS NWs with well controlled particle size. • Tuning of particle size to double power conversion efficiency for CdS NWs/ Bi 2 Se 3 nanoparticles than bare CdS. • Extensively conception and corroboration of solar cells performance and external quantum efficiency with structural, surface morphological, elemental and optical analysis. Core-shell surface architecture with well-tuned shell on one dimensional core is emerging a new field towards energy conversion which can pivot a strategic path in upcoming technologies. Unique Bi 2 Se 3 nanoparticles (NPs) shell with aid of simple, and low-cost successive ionic layer adsorption and reaction (SILAR) onto chemically deposited 1-D CdS nanowires as core has been explored as a first report towards photoelectrochemical (PEC) solar cell application. First report to use of Bi 2 Se 3 nanoparticles (NPs) over CdS NWs as heterostructure partner towards the formation CdS NWs/ Bi 2 Se 3 core-shell surface architecture with aid of simple, low cost and industry scalable chemical methods has been demonstrated. Well-tuned process parameters creates well aligned CdS NWs/ Bi 2 Se 3 NPs heterostructure yielding twofold power conversion efficiency as compared to bare CdS. TEM and FE-SEM analysis suggest formed Bi 2 Se 3 NPs shell has been uniformly decorated onto the surface of CdS NWs core leading to enhanced light absorption by shifting the absorption edge towards red. Designed core-shell heterostructure towards achieved photovoltaic performances has been well understood though structural, surface morphological, optical and elemental (XPS) studies in correlation with photo electrochemical (PEC) solar cell and Mott-Schottky analysis. Interesting, enhanced external quantum efficiency (EQE) due to the expansion of light absorption along with shorter charge recombination is well supported through EIS studies. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract Through simple chemical route, nanoheterojunction has been developed between CdS-nanowires (NWs) as core with PbS nanoparticles as a shell for photoelectrochemical solar cell application. The use of simple, cost effective and industry scalable chemical bath deposition (CBD) and successive ionic layer adsorption and reaction (SILAR) approaches for the deposition of CdS NWs and PbS nanoparticles, respectively has the added advantage. Well-tuned nano particle size of PbS through number of SILAR cycles over wide band gap CdS resulted into optical red shift which maximize the absorption region of solar spectrum responsible for yielding enhancement in light conversion efficiency than bare CdS. Device configured solar cell yields 15 fold enhancement in the power conversion efficiency in liquid configuration due to the well aligned nanoheterojunction between CdS and PbS analysed through photoelectron X-ray spectroscopy. This enhancement in efficiency has been correlated through flat band potential, electron life time, rate of recombination and external quantum efficiency. Graphical abstract Image 1 Highlights • Very easy and low cost method to synthesis CdS NWs/PbS core-shell structure for designing photoelectrochemical solar cell. • 15 fold enhancement in power conversion efficiency for the optimized CdS/PbS core-shell has been achieved successfully. • An in-depth discussion regarding the higher efficiency has been properly correlated with the different characterizations. [ABSTRACT FROM AUTHOR]

Room temperature sequential growth namely, successive ionic layer adsorption and reaction (SILAR) method has been successfully processed towards the controlled growth of silver selenide (Ag 2 Se) nanoparticles onto one dimensional (1D) CdS nanowires (NWs) array. Well controlled size tuning enables well-aligned heterostructure yielding almost four times enhancement (0.34%) in power conversion efficiency compared to the bare CdS NWs (0.09%) in photoelectrochemical (PEC) solar cell assembly. Results are well equipped through structural, surface morphological, optical and elemental oxidation state in correlation with PEC solar cell, external quantum efficiency (EQE), Mott-Schottky (M − S), and electrochemical impedance spectroscopy (EIS) performances. Interestingly, sequential SILAR method produces extremely conformal coverage of Ag 2 Se layer with precise thickness control. The optimum mutualistic contribution from Ag 2 Se and CdS not only broaden the light absorption range but also allows the rapid separation of excited charge carriers at heterostructure interface. • The core-shell nano heterostructure between CdS nanowires (NWs) and Ag 2 Se nanoparticles has been reported for the first time. • The utilization of a simple and inexpensive chemical route to decorate Ag 2 Se NPs onto CdS NWs with controlled particle size is considered state of the art. • Particle size optimization for CdS NWs/Ag 2 Se NPs to get four-fold enhancement in power conversion efficiency than bare CdS NWs. • Photoelectrochemical solar cell performance and external quantum efficiency were extensively conceived and confirmed using structural, morphological, elemental, optical and electrochemical impedance analysis. [ABSTRACT FROM AUTHOR]

[Display omitted] • Solution chemistry approach was used to synthesize high surface area CdS NWs. • Novel phenothiazine based organic dyes were synthesized & used as light harvesters. • Embedded CdS NWs and Organic dyes solar cells were fabricated and characterized. • Dye loaded CdS NWs have shown more efficiency as compared to bare CdS NWs. Synthesis of metal-free organic dyes PDR and PDP based on the phenothiazine core unit have been attempted through solution chemistry approach and anchored on to one dimensional cadmium sulphide nanowires (CdS NWs) to be used as light harvesters in dye sensitized solar cell (DSSC) device application. Simple and cost effective solution chemistry approach leads to enable CdS NWs interconnected nano network. Synthesized dyes have been investigated through optical and electrochemical studies in addition to theoretical calculations using density functional theory (DFT). Dye anchored CdS films cover wider light absorption than bare CdS in the visible part of solar spectrum. The complete device configuration has been assembled as FTO/CdS compact/CdS NWs/Organic dye/electrolyte/Platinum electrode. PDR and PDP sensitized CdS NWs yield 0.24 and 0.28% efficiency which are 2.36 and 2.77 times as compared to bare CdS NWs (0.10%) with sun light of standard conditions of illuminations. External quantum efficiency enhancement is well supported with the obtained results and correlated well with the absorption studies. The present work successfully demonstrates the use of novel synthesized organic dyes as light harvesters. [ABSTRACT FROM AUTHOR]

• Easy and low-cost chemical route to synthesis CdS @Ag 2 S core-shell nanowire at 27°C. • Synthesis of CdS@Ag 2 S core-shell assembly based on negative free energy of formation. • Three-fold efficiency boost by well controlled CdS NWs/Ag 2 S core-shell architecture. • In-depth discussion about the efficiency and correlated with the different analysis. Design and development of cadmium sulphide core with silver sulphide shell assembly in nanowire (NWs) surface architecture has been explored through room temperature, simple chemical route towards photoelectrochemical solar cell application. Incorporation of low band gap Ag 2 S nanoparticles over the outer surface of the chemical bath deposited CdS NWs has been achieved by simple cation exchange route based on negative free energy of formation. Shell optimization has been performed by investigating structure, surface morphologies and optical analyses and correlated with the photovoltaic parameters. Interestingly, core–shell CdS NWs/ Ag 2 S exhibits 1.5 better performance in terms of linear voltammetry, photocurrent transient response and the photo stability than bare CdS. Furthermore, three-fold enhancement in photoelectrochemical conversion efficiency have been observed for optimized FTO/ CdS NWs/Ag 2 S compared to bare FTO/CdS NWs due to the augmented light harvesting and condensed charge recombination. External quantum efficiency exhibits 24% for the optimized CdS NWs/ Ag 2 S core shell structure. Mott-Schottky and electrochemical impedance spectroscopy measurements have been used for better understanding the impact of gradual growth of Ag 2 S over CdS NWs which directly influences the overall photocurrent density of the devices. [ABSTRACT FROM AUTHOR]

• A novel TCF functionalized diketopyrrolopyrrole based dye was design and synthesized. • Optimization geometries of DPP-TCF dye was studied by DFT. • Molar absorptivity of DPP-TCF increase as the incorporation of TCF subunit increasing π-conjugation. • Reversible redox signals in cyclic voltammetry. • DPP-TCF dye/CdS nanowire shows the highest power conversion efficiency (η) 0.427%. Diketopyrrolopyrrole (DPP) functionalized with 2-(3-cyano-4,5,5-trimethylfuran-2(5H)-ylidene) malononitrile (TCF) material coined as DPP-TCF was designed and synthesized. DPP-TCF exhibited strong absorption bands in solution as well as thin-film form. Herein, we report construction of dye sensitized solar cells (DSSCs) based on DPP-TCF anchored on CdS nanowires (NWs) coated on fluorine doped tin oxide (FTO) coated glass substrate with the device architecture FTO/CdS compact/CdS nanowire/ DPP-TCF chromophore/electrolyte/ platinum coated FTO. As-fabricated DSSC device based on DPP-TCF and CdS nanowires exhibited power conversion efficiency (η) of 0.427%. Thus, the present work successfully displayed the utilization of DPP-TCF as an efficient light harvester in DSSC applications. This approach can also be employed to design and development of other DPP based organic molecular chromophores for DSSC applications. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Synthesized CdS thin films revealed mixed cubic and hexagonal phases. • Metal free azo dyes optimized by DFT used for sensitization of CdS NWs. • Azo dye D2 has shown 5 fold increase in solar to electric conversion compared to pristine CdS NWs. • Explored effect of cosensitization of natural dye Betanin on solar to electric conversion. Herein, as-synthesized azo dye (E)-2-isopropyl-5-methyl-4-((4-(4-nitrophenyl) thiazol-2-yl) diazenyl) phenol (D2) has been anchored on a high surface area one dimensional CdS nanowires (NWs) in thin film form. CdS nanowires have been grown through Cd(OH) 2 template formation followed by conversion to CdS by ion-exchange route. The light-electricity conversion efficiency of the CdS-Azo dye-based solar cell has shown about 5-fold remarkable surge (0.159%) compared to the bare CdS (0.03%) with I 3 −/I− redox mediator under standard AM 1.5 illumination (100 mW cm−2). Albeit, the DFT studies revealed a higher band gap for pristine D2, alluringly it has depicted higher light-electricity conversion efficiency among the fabricated thin film solar cells after sensitization. The relative increase in sensitivity after sensitization is attributable to facile dye regeneration. Furthermore, after the co-sensitization of CdS thin film with equimolar cocktails of as-synthesized dyes and a natural dye Betanin (Bn), less efficiency was depicted ascribable to plausible dye aggregation upon blending. [ABSTRACT FROM AUTHOR]

• Complete solid state device with FTO/PANI/PTh/ZnO/Al assembly prepared by absolute wet chemical route. • PANI has been prepared by the simple chemical bath deposition (CBD) method. • Effect of thickness of active layer (PANI) on the solid state device is tested. • The highest value of V oc was obtained as 789 mV with the 3 CBD cycles for PANI. A complete solid state device with FTO/PANI/PTh/ZnO/Al assembly prepared by absolute wet chemical methods including chemical bath deposition (CBD), successive ionic layer adsorption and reaction (SILAR) and spin coating has been studied to investigate the effect of thickness of active PANI layer on device performance. Structural, morphological and chemical bond features have been investigated by using X-ray diffraction, Field Emission Scanning Electron Microscopy and Fourier Transform Infrared spectroscopy of the layers and are discussed herein. Effect of PANI thickness on current-voltage characteristic has been studied under dark and illumination (100 mW/cm2, AM 1.5G, 1 Sun) condition to know the solar cell performance. [ABSTRACT FROM AUTHOR]

In this study, we have inventively developed novel metal-free organic dyes (PPR and PCTR) through a multistep synthetic route. These designed novel dye molecules were integrated onto 1-D CdS nanowires, serving as excellent sensitizer for the efficient light energy harvesting components in the context of dye-sensitized solar cells. Through a facile and efficient approach to solution chemistry, we have attained the unified architecture of CdS nanowires into a multifaceted nano-network, highlighting the absolute efficiency of this approach. Density functional theory (DFT) simulations, united with scrupulous optical and electrochemical investigations, have been employed to assess the sensitizing ability of engineered materials. Remarkably, dye-anchored CdS NWs reveals prolonged light absorption coverage through visible solar spectrum than unmodified CdS nanowire counterparts. Elaborate photovoltaic study reveals, the well-matched energy band alignment, particularly LUMO levels of the PCTR than PPR dye, with CdS NWs, stands as the substratum for the dramatic improvement observed in both the J sc and V oc attributes. This growth interprets into an overwhelming 2.6-fold and 2.0-fold enhancement in the overall solar cell performance for PCTR and PPR dyes respectively, exceeding the ability of CdS NWs under standard light conditions. Improving external quantum efficiency (EQE) and impeccably correlating with results of complex optical investigations. This significant achievement intends to highlight solar energy conversion approaches and alter the field of light-driven technologies. [ABSTRACT FROM AUTHOR]

Controlled growth of different sizes of cadmium selenide (CdSe) nanoparticles over well aligned ZnO nanorods have been performed using successive ionic layer adsorption and reaction (SILAR) technique at room temperature (27 °C) in order to form nano heterostructure solar cells. Deposition of compact layer of zinc oxide (ZnO) by SILAR technique on fluorine doped tin oxide (FTO) coated glass substrate followed by growth of vertically aligned ZnO nanorods array using chemical bath deposition (CBD) at low temperature (<100 °C). Different characterization techniques viz. X‐ray diffractometer, UV–Vis spectrophotometer, field emission scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy have been used to know the structural, optical, morphological and compositional properties of synthesized nano heterostructure. The photovoltaic performance of the cells with variation in SILAR cycles for CdSe and with use of different electrolytes have been recorded as J-V characteristics and the maximum conversion efficiency of 0.63% have been attained with ferro/ferri cyanide electrolyte for 12 cycles CdSe coating over 1-D ZnO nanorods. [ABSTRACT FROM AUTHOR]

Surface coating of CdS nanoparticles over the ZnO nanorods have been performed by using simple successive ionic layer adsorption and reaction at room temperature. Initially, the seed/compact ZnO layer have been deposited via SILAR (successive ionic layer adsorption and reaction) on to fluorine doped tin oxide coated glass (FTO) substrate followed by synthesis of ZnO nanorods by chemical bath deposition method. The synthesized nano heterostructure was characterized by X-ray diffraction (XRD), UV–Vis spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), field emission-scanning electron microscopy (FE-SEM), energy dispersive X-ray analysis (EDX) and high resolution-transmission electron microscopy (HR-TEM) techniques. The photovoltaic performance of the cell was recorded with a conversion efficiency of 0.123% under 100 mW/cm 2 simulated sunlight at AM 1.5G conditions. [ABSTRACT FROM AUTHOR]

Room temperature chemical bath deposition (CBD) method was employed to anchor CdSe quantum dots (QD׳s) on mesoporous TiO 2 , exclusively without using linkers. The sizes of CdSe QD׳s were tuned simply by varying the deposition time in CBD method and uniform coverage of CdSe QD׳s on mesoporous TiO 2 was achieved. The chemical approach provided in the present investigation is free from the post annealing treatment after the growth of QD׳s; essential to lower down the process cost. The red shift in absorption maxima was observed with respect to deposition time in the UV–vis spectra which strongly supports the size quantization effect. Finally, the synthesized CdSe sensitized TiO 2 has successfully demonstrated the potential ability as a quantum dot sensitizer for solar cell application when illuminated with 50 mW/cm 2 intensity (air mass 1.5). [ABSTRACT FROM AUTHOR]

Novel organic dyes PHR and PHP possessing different acceptors have been synthesized, characterized and exploited as effective sensitizers for dye sensitized solar cells. These sensitizers were utilized for the fabrication on newly synthesized CdS nanowires to study the impact of anchor groups on their photovoltaic performance. Optical, electrochemical and photovoltaic properties for the novel dyes and their solar cell devices have been explored to investigate the influence of different anchors on the dyes. The detailed photovoltaic investigation demonstrated that the photovoltaic efficiency of PHP device shows 3.21 times while the PHR device shows 1.87 times than the bare CdS NWs device. This indicates that the dye containing pyridine ring as anchoring group (PHP) works effectively and shows enhancement in the photovoltaic efficiency than the dye containing Rhodanine-3-acetic acid (R3A). Hence, the widely used R3A group for sensitizers may not be the optimal choice for dye sensitized solar cells (DSSCs). The density functional theory (DFT) calculation revealed the proper pathway of electron injection from dye to CdS NWs in pyridine containing dye than in rhodanine dye which is responsible for increase in the efficiency. [Display omitted] • High surface area CdS NWs have been synthesized by effective CBD technique and utilized as photoanodes. • Novel organic dyes PHR and PHP possessing different anchoring groups have been synthesized and exploited as effective sensitizers for DSSC. • Photovoltaic efficiency of PHP device shows 3.21 times while the PHR device shows 1.87 times than the bare CdS NWs device. • Dye containing pyridine ring works effectively and shows enhancement in the photovoltaic efficiency than the dye containing Rhodanine-3-acetic acid. • The DFT calculation revealed the proper pathway of electron injection from dye to CdS NWs in PHP than in PHR dye which is responsible for increase in the efficiency. [ABSTRACT FROM AUTHOR]

The DPP1 and DPP2 coated CdS nanowire was employed for DSSC based solar cell applications. DPP2 dye exhibited higher power conversion efficiency (PCE) 0.268%as compared to DPP10.195%, under standard illumination of sunlight (AM 1.5 G, 100 mW/cm2). [Display omitted] • Novel series of DPP compounds is designed and synthesized. • Influences of thiophene ring system on AIE and CdS solar cells are investigated. • Impacts of the DPP1 and DPP2 on CdS nanowire solar cell were studied. • Design criteria for DPP suggested new development in the field. • DPP2 exhibits higher power conversion efficiency as compare to DPP1 and CdS nanowire. We designed and synthesized two diketopyrrolopyrrole (DPP) derivatives (DPP1 and DPP2) which are substituted with phenyl and thiophene moieties in between DPP core and merocyanine dyes, respectively. The introduction of thiophene ring subunit at core position endows DPP2 significantly alters the photophysical, electrochemical and aggregation induces enhanced emissive (AIEE) properties compared to those of DPP1. As a practical point of view, we successfully employed DPP1 and DPP2 as sensitizer on CdS nanowires for fabrication of dye sensitized solar cell (DSSCs). The DSSC based on DPP2 (0.268%) dye yielded higher power conversion efficiency (PCE) as compared to DPP1 (0.195%) under standard illumination of Sunlight (AM 1.5 G, 100 mW/cm2). The basis for this different behaviour has been discussed. [ABSTRACT FROM AUTHOR]