•The UV–VIS absorption spectra indicate a broad range of light absorption for PbS/CdS/ZnS quantum dots.•SILAR cycle has a direct impact on the size and band gap of quantum dots.•Six devices were ...fabricated with different HTLs and metal contacts.•Samples were characterized by XRD, SEM and EDX.•Highest power conversion efficiency of 2.17 % was achieved with P3HT/Au.
Quantum dots, as a sensitizer in quantum dot-sensitized solar cells (QDSSCs), hold the promise of revolutionizing solar energy conversion. This research mainly focuses on employing PbS/CdS/ZnS quantum dots (QDs) as both light harvesters and passivation layers in QDSSCs, which are directly synthesized onto the pre-deposited TiO2 substrate through the Successive Ionic Layer Adsorption and Reaction (SILAR) technique. Particularly, the sample with a composition of 2 cycles of PbS, 6 cycles of CdS, and 2 cycles of ZnS (2/6/2) exhibited a wide-ranging and intense absorption spectrum, attributed to the reduction in band gap with escalation in number of SILAR cycles. The prepared samples underwent analysis through characterization methods, including SEM and XRD, and the elemental composition was examined using EDX spectroscopy. Subsequently, the 2/6/2 sample was employed as a sensitizer, with P3HT and PEDOT:PSS serving as the hole transport layers (HTL). For the metal contacts, thermally evaporated gold (Au), silver (Ag), and Ag paste were used in the fabrication of six distinct devices. FTO/TiO2/PbS/CdS/ZnS/P3HT/Au shows the best performance demonstrating PCE of 2.17 %, Jsc of 7.9 mA/cm2 Voc of 0.54 V and FF of 0.51. However, overall efficiency dropped significantly for other configurations. Additionally, impedance spectroscopic analysis revealed a notably low series resistance for the P3HT/Au configuration.
•PbS QDs demonstrate significant photosensitizing properties, owing to tunable size and band gap.•SILAR is a simple and low-cost synthesis technique, here we utilized it for synthesis of PbS ...QDs.•Three devices were fabricated with one, two and three SILAR cycles.•Energy band gap and size of QDs were found via Tauc plot and HBM model respectively.•Highest power conversion efficiency of 2.07 % was achieved for two SILAR cycles.
Lead sulfide (PbS) quantum dots (QDs) with their customizable and precise energy levels, have emerged as highly promising photosensitizers in quantum dots sensitized solar cells (QDSSCs). This research focuses on fabricating high-performance QDSSCs anchored on PbS QDs sensitized mesoporous titania coated FTO electrodes. The PbS QDs were grown on mesoporous TiO2 through the Successive Ionic Layer Absorption and Reaction (SILAR) method. The optical properties were analyzed using UV–visible absorption spectroscopy, revealing that the SILAR cycles impacted the size and band gap of the PbS QDs. By analyzing the absorption data and the hyperbolic band model (HBM), the size of the PbS QDs were estimated to be 1.65 nm, 2.126 nm, 2.326 nm, 2.5692 nm, and 3.048 nm for 1 to 5 SILAR cycles, respectively. The effect of SILAR cycles was investigated, demonstrating a direct correlation between the number of SILAR cycles and the photovoltaic performance of the device. The maximum power conversion efficiency of 2.07 % was attained using 2 SILAR cycles, in contrast to 1.33 % and 1.63 % obtained with one and three SILAR cycles, respectively. Furthermore, impedance spectroscopy (IS), (Cs-V) (Rs-V) was employed at different frequencies, highlighting lowest series resistance for 2 SILAR cycles confirming its highest photovoltaic performance. Moreover, The utilization of a low-cost polysulfide electrolyte and carbon electrode has yielded superior or comparable outcomes compared to previously reported data.
Application of MXene materials in perovskite solar cells (PSCs) has attracted considerable attention owing to their supreme electrical conductivity, excellent carrier mobility, adjustable surface ...functional groups, excellent transparency and superior mechanical properties. This article reviews the progress made so far in using Ti
C
T
MXene materials in the building blocks of perovskite solar cells such as electrodes, hole transport layer (HTL), electron transport layer (ETL) and perovskite photoactive layer. Moreover, we provide an outlook on the exciting opportunities this recently developed field offers, and the challenges faced in effectively incorporating MXene materials in the building blocks of PSCs for better operational stability and enhanced performance.
This paper reports on the thin film characterization of a synthesized small molecular semiconductor
N
-butyl-
N
′-(6-hydroxyhexyl) perylene-3,4,9,10-tetracarboxylic acid diimide (
N
-BuHHPDI) and its ...potential use in Ag/
N
-BuHHPDI/PEDOT:PSS/
p
-Si heterojunction device. The device is fabricated using spin coating of a conducting polymer PEDOT:PSS on
p
-Si substrate followed by thermal deposition of a 100-nm-thin layer of
N
-BuHHPDI. To complete the fabrication of Ag/
N
-BuHHPDI/PEDOT:PSS/
p
-Si heterostructure, silver (Ag) is used as the top electrode. The device shows non-ohmic and asymmetrical current–voltage (
I
–
V
) characteristics in dark conditions at 25°C which confirm the successful formation of rectifying heterojunction. Various diode parameters such as ideality factor (
n
), barrier height (
ϕ
b
), series resistance (
R
s
) and charge carrier mobility across the interface of the heterojunction are measured from the
I
–
V
characteristics. The non-ideal behavior of the diode is correlated with the film morphology obtained by atomic force microscopy. Fourier transformed infrared spectroscopy is performed to confirm the successful preparation of
N
-BuHHPDI. The fluorescence lifetime (22 ns) of the
N
-BuHHPDI thin film is measured via fluorescence spectroscopy. Different charge conduction mechanisms including the dominant one are studied for the fabricated device.
Since its invention in 2009, Perovskite solar cells (PSCs) has attracted great attention because of its low cost, numerous options of efficiency enhancement, ease of manufacturing and ...high-performance. Within a short span of time, the PSC has already outperformed thin-film and multicrystalline silicon solar cells. A current certified efficiency of 25.2% demonstrates that it has the potential to replace its forerunner generations. However, to commercialize PSCs, some problems need to be addressed. The toxic nature of lead which is the major component of light absorbing layer, and inherited stability issues of fabricated devices are the major hurdles in the industrialization of this technology. Therefore, new researching areas focus on the lead-free metal halide perovskites with analogous optical and photovoltaic performances. Tin being nontoxic and as one of group IV(A) elements, is considered as the most suitable alternate for lead because of their similarities in chemical properties. Efficiencies exceeding 13% have been recorded using Tin halide perovskite based devices. This review summarizes progress made so far in this field, mainly focusing on the stability and photovoltaic performances. Role of different cations and their composition on device performances and stability have been involved and discussed. With a considerable room for enhancement of both efficiency and device stability, different optimized strategies reported so far have also been presented. Finally, the future developing trends and prospects of the PSCs are analyzed and forecasted.
A step-by-step heat treatment was applied to ruthenium-based N719 dye solution for its potential application in dye-sensitized solar cells (DSSCs). The effects were analyzed and compared with ...standard untreated devices. A significant increase in short circuit current density was observed by employing a step-by-step heating method for dye solution in DSSCs. This increase of
J
sc
is attributed to the enhancement in dye adsorption by the surface of the semiconductor and the higher number of charge carriers generated. DSSCs fabricated by a heated dye solution have achieved an overall power conversion efficiency of 8.41% which is significantly higher than the efficiency of 7.31% achieved with DSSCs fabricated without heated dye. Electrochemical impedance spectroscopy and capacitance voltage studies were performed to understand the better performance of the device fabricated with heated dye. Furthermore, transient photocurrent and transient photovoltage measurements were also performed to gain an insight into interfacial charge carrier recombinations.
This paper reports on electrical characterization of ITO/PEDOT:PSS/PTCDA/Ca/Ag device based on 3,4,9,10-perylene tetracarboxylic dianhydride (PTCDA) and calcium (Ca) buffer layer with improved ...junction properties. The I–V characteristics have been utilized to extract various electrical parameters such as ideality factor (n), barrier height (ϕB) and series resistance Rs, which are found to be 1.9, 0.79eV and 2.5kΩ, respectively. The device shows good rectifying behavior, with a rectification ratio of 528, and also field-lowering mechanism with a linear dependence of log I on V1/2. The device reported in the present work shows 50% improvement in the rectification ratio and ideality factor as compared to our previously fabricated device. It appears from the experimental data that the transport mechanism in the PTCDA thin film is dominated by the Poole–Frenkel model of thermionic emission, which may be associated with high density of structural defects or traps present in the film.
•The surface morphology of the organic material CoPc is investigated via AFM.•We have fabricated the heterojunction of CoPc with n-Si and its diode parameters are calculated.•The photo response of ...the heterojunction is also studied to show the potential of our heterojunction to be used as photo-sensor.
We report fabrication and characterization of heterojunction diode based on organic semiconductor cobalt phthalocyanine (CoPc) with n-silicon. The electrical characteristics of the CoPc/n-Si junction, along with its photo response, are investigated by current–voltage (I–V) measurements. The morphological properties of the CoPc thin film are investigated using atomic force microscopy (AFM). The I–V characteristics of the junction show rectifying behavior with a rectification ratio of 145 at the bias voltages of ±3.6V. The diode parameters such as ideality factor n, barrier height φb and series resistance Rs were determined from the I–V characteristics, which were confirmed by Cheung’s function. The conduction mechanism of the diode is also studied to calculate mobility of the CoPc film. The photo response of the device shows that it can be used as photo-sensor.
Due to the tremendous increase in power conversion efficiency (PCE) of organic-inorganic perovskite solar cells (PSCs), this technology has attracted much attention. Despite being the fastest-growing ...photovoltaic technology to date, bottlenecks such as current density-voltage (
) hysteresis have significantly limited further development. Current density measurements performed with different sweep scan speeds exhibit hysteresis and the photovoltaic parameters extracted from the current density-voltage measurements for both scan directions become questionable. A current density-voltage measurement protocol needs to be established which can be used to achieve reproducible results and to compare devices made in different laboratories. In this work, we report a hysteresis analysis of a hole-transport-material-free (HTM-free) carbon-counter-electrode-based PSC conducted by current density-voltage and impedance spectra measurements. The effect of sweep scan direction and time delay was examined on the
characteristics of the device. The hysteresis was observed to be strongly sweep scan direction and time delay dependent and decreased as the delay increased. The
analysis conducted in the reverse sweep scan direction at a lower sweep time delay of 0.2 s revealed very large increases in the short circuit current density and the power conversion efficiency of 57.7% and 56.1%, respectively, compared with the values obtained during the forward scan under the same conditions. Impedance spectroscopy (IS) investigations were carried out and the effects of sweep scan speed, time delay, and frequency were analyzed. The hysteresis was observed to be strongly sweep scan direction, sweep time delay, and frequency dependent. The correlation between
and IS data is provided. The wealth of photovoltaic and impendence spectroscopic data reported in this work on the hysteresis study of the HTM-free PSC may help in establishing a current density-voltage measurement protocol, identifying components and interfaces causing the hysteresis, and modeling of PSCs, eventually benefiting device performance and long-term stability.
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