Butyric Acid Methyl Ester Research Articles

Changes in Optimal Ternary Additive Loading when Processing Large Area Organic Photovoltaics by Spin‐ versus Blade‐Coating Methods

As we move toward roll‐to‐roll processing of organic photovoltaics (OPVs), it is important to validate the process and the ink formulations. A poly[[9‐(1‐octylnonyl)‐9Hcarbazole‐2,7‐diyl]‐2,5‐thiophenediyl‐2,1,3‐benzothiadiazole‐4,7 diyl2,5thiophenediyl]:[6,6]‐phenyl C71 butyric acid methyl ester (PCDTBT:PC71BM)‐based OPV with an increase in power conversion efficiency (PCE) from 4.6% up to 5.4% by incorporating bis(tri‐hexylsiloxy) silicon phthalocyanine ((3HS)2‐SiPc) NIR absorbing ternary additives on indium tin oxide (ITO)/polyethyleneterapthalate (PET) flexible substrate with active area of 1 cm2 under simulated AM 1.5G one sun irradiation. Maximum PCE of the ternary OPVs was obtained with 5 wt% of (3HS)2‐SiPc added when processing the active layer by spin coating, whereas the addition of 10 wt% of (3HS)2‐SiPc is required for the maximization of PCE when processing the films by blade coating. The importance of processing conditions when optimizing the concentration of ternary additives in bulk heterojunction (BHJ) OPVs is demonstrated.

Solution-processable small molecule based all-organic ultraviolet photodetector

A tetramethoxyfluorene derivative (TMD) based small molecule (C53H54O4) has been used as a donor in a bulk-heterojunction donor-acceptor blend system to realize room temperature solution-processed ultraviolet (UV) photodetector. A systematic opto-electronic study to optimize the weight ratio of the blend of TMD and a common acceptor [6,6]-phenyl-C61 butyric acid methyl ester (PCBM) is presented in this report. The fabricated detector is found to cover the most harmful UVA region while transmitting nearly the entire visible spectrum of light. The responsivity of 6 × 10−2 A/W, specific detectivity of 9.36 × 1011Jones and photosensitivity of 105, which are on par with the existing UV photodetectors reported in the literature, are obtained at the wavelength 394 nm under zero bias condition.

High‐Efficiency Carbon‐Based CsPbIBr2 Solar Cells with Interfacial Energy Loss Suppressed by a Thin Bulk‐Heterojunction Layer

The CsPbIBr2 perovskite has obvious advantages in balancing the stability and efficiency in inorganic perovskite solar cells (PSCs). Its large bandgap of 2.08 eV, which leads to a narrow spectral absorption (<600 nm), is the key limit to yielding a high power conversion efficiency (PCE). Herein, it is demonstrated that by integrating a thin bulk‐heterojunction (BHJ) layer (19 nm) composed of the typical poly (3‐hexylthiophene‐2,5‐diyl) and [6,6]‐phenyl methyl C61 butyric acid methyl ester (P3HT:PCBM) with CsPbIBr2 perovskite, a carbon‐based all‐inorganic PSC achieves a much higher champion PCE (11.54%) than the original CsPbIBr2 device (8.87%), and the value is also at the highest PCE level of all‐inorganic CsPbIBr2 PSCs. The integration of a thin BHJ layer brings an expanded light absorption range, better charge transfer dynamics, suppressed interfacial energy loss, and improved long‐term stability. The unencapsulated CsPbIBr2 PSC with an integrated BHJ layer shows excellent long‐term stability in an ambient atmosphere with high relative humidity (RH ≈ 45%, T ≈ 25 °C). Therefore, the BHJ integration is an effective strategy on the road to industrialization of carbon‐based all‐inorganic PSCs with low cost, high efficiency, and excellent long‐term stability.

Impact of Potential‐Induced Degradation on Different Architecture‐Based Perovskite Solar Cells

Organic–inorganic perovskites photovoltaic materials are considered as one of the promising candidates for the emerging photovoltaic (PV) sector. It has drawn tremendous attention from fundamental research and PV industries, due to its high efficiency, chemical properties, and low fabrication cost. But, its lifetime under real field operation is always the major obstacle toward commercialization. Potential‐induced degradation (PID) is known as the common reliable threat in the established commercial PV technologies which lead to catastrophic failure within a short time. Thus, it is essential to enable reliability assessment of PID on the precommercial development stage of perovskite photovoltaics to further enrich the confidence by identifying, eliminating, and developing an understanding of the possible degradation mechanism in the field condition. In this article, different architecture‐based perovskite solar cells are studied to reveal the degradation mechanism under PID for the first time. The results show that PSCs of n–i–p with a phenyl C61 butyric acid methyl ester (PCBM) layer have good stability under PID compared with other treated structures with only 4% degradation after 18 h.

Unsymmetrical zinc phthalocyanines containing thiophene and amine groups as donor for bulk heterojunction solar cells.

Photovoltaic technology is an alternative resource for renewable and sustainable energy and low costs organic photovoltaic devices such as bulk-heterojunction (BHJ) solar cells, which are selective candidates for the effective conversion of solar energy into electricity. Asymmetric phthalocyanines containing electron acceptor and donor groups create high photovoltaic conversion efficiency in dye sensitized solar cells. In this study, a new unsymmetrical zinc phthalocyanine was designed and synthesized including thiophene and amine groups at peripherally positions for BHJ solar cell. The structure of the targeted compound (4) was characterized comprehensively by FT-IR, UV–Vis, 1H-NMR, and MALDI-TOF MS spectroscopies. The potential of this compound in bulk heterojunction (BHJ) photovoltaic devices as donor was also researched as function of blend ratio (blend ratio was varied from 0.5 to 4). For this purpose, a series of BHJ devices with the structure of fluorine doped indium tin oxide (FTO)/poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)/ ZnPc:[6,6]- phenyl-C61- butyric acid methyl ester (PCBM) blend/Al with identical thickness of ZnPc:PCBM layer were fabricated and characterized. Photo current measurements in 4 revealed that the observed photo current maximum is consistent with UV-vis spectra of the compound of 4. Preliminary studies showed that the blend ratio has a critical effect on the BHJ device performance parameters. Photovoltaic conversion efficiency of 6.14% was achieved with 4 based BHJ device.

A Highly Strained All-Phenylene Conjoined Bismacrocycle.

Herein, we report the precise synthesis of a 3D highly strained all-phenylene bismacrocycle, termed conjoined (1,4)[10]cycloparaphenylenophane (SCPP[10]). This structure consists of a twisted benzene ring which is bridged twice by phenylene units anchored in two para-positions. The conjoined structure of SCPP[10] was confirmed in real space at the atomic scale by scanning tunneling microscopy. Theoretical calculations indicate that this bismacrocycle has a very high strain energy of 110.59 kcal mol-1 and the largest interphenylene torsion angle of 46.07° caused by multiple repulsive interactions. Furthermore, a 1:2 host-guest complex of SCPP[10] and [6,6]-phenyl-C61 -butyric acid methyl ester was investigated, which represents the first peanut-shaped 1:2 host-guest complex based on bismacrocycles.

Ultrasonically Processed WSe2 Nanosheets Blended Bulk Heterojunction Active Layer for High-Performance Polymer Solar Cells and X-ray Detectors.

Two-dimensional (2D) tungsten diselenide (WSe2) has attracted considerable attention in the field of photovoltaic devices owing to its excellent structure and photoelectric properties, such as ordered 2D network structure, high electrical conductivity, and high mobility. For this test, we firstly prepared different sizes (NS1–NS3) of WSe2 nanosheets (NSs) through the ultrasonication method and characterized their structures using the field emission scanning electron microscope (FE-SEM), Raman spectroscopy, and X-ray powder diffraction. Moreover, we investigated the photovoltaic performance of polymer solar cells based on 5,7-Bis(2-ethylhexyl)benzo[1,2-c:4,5-c′]dithiophene-4,8-dione(PBDB-T):(6,6)-phenyl-C71 butyric acid methyl ester (PCBM) with different WSe2 NSs as the active layer. The fabricated PBDB-T:PCBM active layer with the addition of NS2 WSe2 NSs (1.5 wt%) exhibited an improved power conversion efficiency (PCE) of 9.2%, which is higher than the pure and NS1 and NS3 WSe2 blended active layer-encompassing devices. The improved PCE is attributed to the synergic enhancement of exciton dissociation and an improvement in the charge mobility through the modified active layer for polymer solar cells. Furthermore, the highest sensitivity of 2.97 mA/Gy·cm2 was achieved for the NS2 WSe2 NSs blended active layer detected by X-ray exposure over the pure polymer, and with the NS1 and NS2 WSe2 blended active layer. These results led to the use of transition metal dichalcogenide materials in polymer solar cells and X-ray detectors.

An adequate avenue towards well-designed PBDT-DTNT:PCBM active layers via quantum dot/conductive polymer configurations

Graphene quantum dots (GQD) and carbon quantum dots (CQD) were employed to develop the patterned GQD/CQD/poly[benzodithiophene-bis(decyltetradecyl-thien) naphthothiadiazole] (PBDT-DTNT) short/long chain, crab-like GQD/semicrab-like CQD/poly(3-hexylthiophene) (P3HT) short chain, and pellet-like GQD/CQD/P3HT long chain supramolecules. Nanostructures were used in roles of modifier, donor, and acceptor constituents in ternary (PBDT-DTNT:[6,6]-phenyl-C71 butyric acid methyl ester (PC71BM)) and binary photoactive layers. Application of pre-designed patterned quantum dot (QD)/PBDT-DTNT short chain nano-hybrids as morphology modifier promoted the performance up to 4.79%. P3HT-based supramolecules acted conspicuously better than PBDT-DTNT ones. The highest efficacies of 7.14 and 6.24% were detected in PBDT-DTNT:PC71BM:GQD/P3HT short chain (14.63 mA cm–2, 68.71%, 0.71 V and 287 Ω cm2) and PBDT-DTNT:PC71BM:CQD/P3HT short chain (13.35 mA cm–2, 66.79%, 0.70 V and 447 Ω cm2) systems, respectively. In addition to ternary photovoltaics, the binary devices were fabricated using the QDs and their associated supramolecules as donor and acceptor agents. Exactly similar to ternary cells, the crab/semicrab-like and pellet-like nano-hybrids, acted better than the PBDT-DTNT patterned nano-hybrids. The best results were recorded for PBDT-DTNT:GQD/P3HT short chain (2.93%) and PBDT-DTNT:CQD/P3HT short chain (2.67%) solar cells. In second type of binary photovoltaics, the QDs and their correlated supramolecules were utilized as electron donor and a maximum performance of 0.22% was acquired.

Isomer‐Dependent Photovoltaic Properties of the [6,6]‐Phenyl‐C61 (or C71)‐Butyric Acid Methyl Esters

Isomerism is common in fullerene derivatives, and the isomer‐dependent photovoltaic performance of fullerene derivatives is envisaged recently. This review article outlines recent progresses on isomerism of [6,6]‐phenyl‐C61 (or C71)‐butyric acid methyl esters (PCBMs), one of the most prevalent electronic acceptors in organic or perovskite solar cells. Recent developments about the effects of PCBMs isomers on the photovoltaic performance and device stability of organic or perovskite solar cells are summarized, including the mono‐ and bis‐adduct of PC71BM as well as the bis‐adduct of PC61BM. The open questions and future directions with involvement of isomeric PCBMs are also discussed.

In-plane oriented CH3NH3PbI3 nanowire suppression of the interface electron transfer to PCBM* *Projected supported by the National Natural Science Foundation of China (Grant Nos. 21503066 and 61904048), the Fundamental Research Project from Shenzhen Science and Technology Innovation Committee (Grant No. JCYJ20180302174021198), the Natural Science Foundation of Hebei Province, China (Grant No. F2017201136), and the Foundation of Hebei Educational Committee (Grant

One-dimensional nanowire is an important candidate for lead-halide perovskite-based photonic detectors and solar cells. Its surface population, diameter, and growth direction, etc., are critical for device performance. In this research, we carried out a detailed study on electron transfer process at the interface of nanowire CH3NH3PbI3(N-MAPbI3)/Phenyl C61 butyric acid methyl-ester synonym (PCBM), as well as the interface of compact CH3NH3PbI3(C-MAPbI3)/PCBM by transient absorption spectroscopy. By comparing the carrier recombination dynamics of N-MAPbI3, N-MAPbI3/PCBM, C-MAPbI3, and C-MAPbI3/PCBM from picosecond (ps) to hundred nanosecond (ns) time scale, it is demonstrated that electron transfer at N-MAPbI3/PCBM interface is less efficient than that at C-MAPbI3/PCBM interface. In addition, electron transfer efficiency at C-MAPbI3/PCBM interface was found to be excitation density-dependent, and it reduces with photo-generation carrier concentration increasing in a range from 1.0 × 1018 cm−3–4.0 × 1018 cm−3. Hot electron transfer, which leads to acceleration of electron transfer between the interfaces, was also visualized as carrier concentration increases from 1.0 × 1018 cm−3–2.2 × 1018 cm−3.

A comparative study of PffBT4T-2OD/EH-IDTBR and PffBT4T-2OD/PC71BM organic photovoltaic heterojunctions

In order to clarify the different photovoltaic performance and “burn-in” degradation mechanism, the electron donor poly[(5,6-difluoro-2,1,3-benzothiadiazol-4,7-diyl)-alt-(3,3′″-di(2-octyldodecyl)-2,2′;5′,2″;5″,2′″-quaterthiophen-5,5′″-diyl)] (PffBT4T-2OD), fullerene derivative acceptor [6,6]-phenyl C71 butyric acid methyl ester (PC71BM) and the nonfullerene acceptor indacenodithiophene core flanked with benzothiadiazole and rhodanine groups with the branched (2-ethylhexyl) chains (coded as EH-IDTBR) were selected to construct PffBT4T-2OD/EH-IDTBR and PffBT4T-2OD/PC71BM complexes as heterojunction interface models. The geometries, electronic structures, excitation properties and the rates of electron processes were extensively explored based upon quantum chemistry calculations. The results indicate that the light harvesting capability of EH-IDTBR is far better than that of PC71BM. Most of excited states of PffBT4T-2OD and EH-IDTBR exhibit intramolecular charge transfer characters. Compared with PffBT4T-2OD/PC71BM, the better planarity, stronger non-bonding interactions, and the hybrid excited states, as well as the larger electrostatic potential difference between the donor and acceptor of PffBT4T-2OD/EH-IDTBR are responsible for its better photovoltaic performance and the lower “burn-in” degradation. Although the rates of charge recombination of PffBT4T-2OD/EH-IDTBR complex is larger, its faster rates of exciton dissociation and charge transfer processes can be helpful to resist “burn-in” degradation. The results are helpful to develop novel OPV materials that are resistant to “burn-in” degradation.

Stabilizing Fullerene for Burn-in-Free and Stable Perovskite Solar Cells under Ultraviolet Preconditioning and Light Soaking.

It is crucial to make perovskite solar cells sustainable and have a stable operation under natural light soaking before they become commercially acceptable. Herein, a small amount of the small molecule bathophenanthroline (Bphen) is introduced into [6,6]-phenyl-C61 -butyric acid methyl ester and it is found that Bphen can stabilize the C60 -cage well through formation of much more thermodynamically stable charge-transfer complexes. Such a strengthened complex is used as an interlayer at the in-light perovskite/SnO2 side to achieve a champion device with efficiency of 23.09% (certified 22.85%). Most importantly, the stability of the resulting devices can be close to meeting the requirements of the International Electrotechnical Commission 61215 standard under simulated UV preconditioning and light-soaking testing. They can retain over 95% and 92% of their initial efficiencies after 1100 h UV irradiation and 1000 h continuous illumination of maximum power point tracking at 60°C, respectively.

Sulfonate-Conjugated Polyelectrolytes as Anode Interfacial Layers in Inverted Organic Solar Cells.

Conjugated polymers with ionic pendant groups (CPEs) are receiving increasing attention as solution-processed interfacial materials for organic solar cells (OSCs). Various anionic CPEs have been successfully used, on top of ITO (Indium Tin Oxide) electrodes, as solution-processed anode interlayers (AILs) for conventional devices with direct geometry. However, the development of CPE AILs for OSC devices with inverted geometry is an important topic that still needs to be addressed. Here, we have designed three anionic CPEs bearing alkyl-potassium-sulfonate side chains. Their functional behavior as anode interlayers has been investigated in P3HT:PC61BM (poly(3-hexylthiophene): [6,6]-phenyl C61 butyric acid methyl ester) devices with an inverted geometry, using a hole collecting silver electrode evaporated on top. Our results reveal that to obtain effective anode modification, the CPEs’ conjugated backbone has to be tailored to grant self-doping and to have a good energy-level match with the photoactive layer. Furthermore, the sulfonate moieties not only ensure the solubility in polar orthogonal solvents, induce self-doping via a right choice of the conjugated backbone, but also play a role in the gaining of hole selectivity of the top silver electrode.

Modelling and Calculation of Characteristic Parameters of the Active and Buffer Layers in Organic Solar Cell

Background: The active layer not only must have a strong light absorption in the visible spectrum but must also be sufficient for charge carrier transport to the electrodes. Electrons in conducting polymer transport by hopping between different energy levels resulted in much lower charge mobility. Therefore, the thickness of the active layer must be limited, so the separated charge can reach the corresponding electrodes without recombination. However, a thin active layer has weaker light absorption, resulting in the low photogenerated current in organic solar cell devices. Furthermore, buffer layers usually have high charge mobility, which in turn would enhance the transportation of charge from the active layer to electrodes. Metal oxides have been studied to be used as a cathode buffer layer, such as titanium dioxide (TiO2), zinc oxide (ZnO), etc. Objective: In this work, behaviors of the photon-electrical characteristics with variation in thickness of the active (poly(3-hexylthiophene-2,5-diyl) and phenyl-C61 butyric acid methyl ester blend) and buffer (zinc oxide) layers were investigated. Methods: The influences of the thickness of the active and buffer layers on characteristic parameters of organic solar cells were investigated by solving the drift and diffusion equation with the photogenerated current given by the Hetch equation. Results: The optimum thickness was obtained around 100 nm and below 10 nm for the active and the ZnO buffer layers, respectively. Conclusion: Thinner active layer resulted in lower photocurrent due to poor light absorption while at 150 nm thick and above, PCE of the device reduced rapidly because of the high recombination rate of photogenerated electron-hole pairs. ZnO buffer layer was used as an electron transport layer and a hole blocking layer in order to improve the cell’s performance. The addition of ZnO enhanced the PCE up to 2.48 times higher than the conventional device.

Effect of 1,8-Diiodooctance additive on the charge carriers behavior in the PCPDTBT:PC71BM BHJ films investigated by using electric-field-induced optical second-harmonic generation measurement

Electric-field-induced optical second harmonic generation (EFISHG) measurement was conducted to investigate the effect of 1,8-diiodooctane (DIO) additive, which is relevant to improve the efficiency of bulk heterojunction (BHJ) solar cells, on carrier behaviors in the BHJ layer, where the BHJ layer is a blend of [6,6]-phenyl C71 butyric acid methyl ester (PC71BM) and regioregular poly [2,6-(4,4-bis-(2-Ethylhexyl)-4H-cyclopentane [2,1-b;3,4-b′] dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)] (PCPDTBT). Using the laser wavelength of 1000 nm, we could selectively observe the electric field in the PCPDTBT phase of BHJ layer, which allowed us to determine the difference in charge accumulation at the interface with and without DIO. With adding DIO, a decrease in interfacial stored charge was observed, and this plays a role in improving the efficiency by about 25%. The DIO modified the internal field distribution so that the electric field promotes the electrons toward the ITO electrode and holes toward the PEDOT:PSS/Au electrode.

Identification of Organic Volatile Markers Associated with Aroma during Maturation of Strawberry Fruits.

In the present study, organic volatile markers of three strawberry varieties (Albion, Festival and Frontera) during the maturation process were investigated. Forty metabolites associated with aroma in fresh strawberries were monitored during seven stages of maturation using gas chromatography–mass spectrometry (GC-MS) equipped with headspace-solid phase microextraction (HS-SPME). The data were evaluated using multivariate analysis to observe correlations between the organic volatile compound profile and the seven phenological stages of maturation for each strawberry variety. The dynamic levels of butanoic acid methyl ester, hexanoic acid methyl ester, octylcyclohexane, cyclohexane,1,1,2-trimethyl, linalool, tetradecane, and α-muurolene underwent distinctive changes in concentration during the maturation process. The multivariate analysis also allowed the identification of these compounds as possible volatile markers to measure the maturation of strawberry fruits in all three varieties. These findings highlight the importance of the timing of harvest and maturation stage in each variety to preserve or improve the desirable aromatic characteristics of strawberry fruits.

Morphology optimization of organic solar cells enabled by interface engineering of zinc oxide layer with a conjugated organic material

A diphenylphosphine-oxide-based conjugated organic molecule, ((1,3,5-triazine-2,4,6-triyl)tris(benzene-3,1-diyl))tris(diphenylphosphine oxide) (PO-T2T), was doped into ZnO to improve the characteristics of the electron transport layer (ETL) in inverted organic solar cells (OSCs). A series of characterization techniques were carried out to demonstrate the function of PO-T2T in film aspect, including transmittance, atomic force microscopy (AFM), transmission electron microscopy (TEM), water contact angle and grazing incidence wide angle X-ray scattering (GIWAXS). Light dependent, space-charge-limited current, exciton dissociation possibility were aimed to explore the influence of PO-T2T for internal carrier behaviors based on PTB7-Th: PC 71 BM system. It's found that the PO-T2T doped ETLs played a role in morphology optimization of ETL and undermined the trap-assistant recombination through filling the defects ZnO itself had, simultaneously. Besides, the electron mobility was also improved. With the optimized functionalities, the OSCs' efficiency based on fullerene system Poly[4,8- bis(5-(2-Ethylhexyl)thiophen-2-yl) benzo [1,2-b:4,5-b′] dithiophene-co-3-fluorothieno [3,4-b] thiophene-2-carboxylate] (PTB7-Th): [6,6]-Phenyl C71 butyric acid methyl ester (PC 71 BM) was improved from 9.03% to 9.84%. Finally, when this strategy was applied into another hot-topic system, poly((2,6-(4,8-bis(5-(2-ethylhexyl-3- fluoro)thiophen-2-yl)-benzo[1,2-b:4,5-b′]dithiophene))-alt-(5,5- (1′,3′-di-2-thienyl)-5′,7′-bis(2-ethylhexyl)benzo[1′,2′-c:4′,5′-c′] dithiophene-4,8-dione)) (PBDB-TF):2,2′-((2Z,2′Z)-((12,13-bis(2- ethylhexyl)-3,9-diundecyl-12,13-dihydro-[1,2,5]thiadiazolo[3,4-e] thieno[2,″3″:4′,5′]thieno[2′,3′:4,5]pyrrolo[3,2-g]thieno[2′,3′:4,5] thieno[3,2-b]indole-2,10-diyl)bis(methanylylidene))bis(5,6-difluoro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile (Y6), a high PCE of 16.34% was obtained. These results demonstrated that the PO-T2T had a positive role in OSC performance improvement. • OSCs based on PM6:Y6 achieved a PCE of 16.34% from 15.44%. • The morphology of PO-T2T doped ETL was more feasible for the form of the active layer. • The defects in ZnO were weakened and the electron collection was facilitated.

Carbon/graphene quantum dot and conjugated polymer nanostructures impart unprecedented high efficiencies in routine P3HT:PCBM photovoltaics

Graphene quantum dot (GQD) and carbon quantum dot (CQD) nanoparticles were employed to fabricate the crab-like GQD/poly(3-hexylthiophene) (P3HT) and semicrab-like CQD/P3HT short chain, pellet-like GQD/P3HT and CQD/P3HT long chain, GQD/P3HT nanofiber and CQD/P3HT nanofiber supramolecules. The P3HT crystals were composed of face-on ((100) and (002) prisms) and edge-on ((020) and (002) growth planes) oriented chains. The lowest d-spacing values were acquired for the QD decorated P3HT nanofibers (d(100) = 13.41–13.46 Ǻ and d(020) = 3.39–3.43 Ǻ). To investigate the function of designed supramolecules in roles of morphology modifier, donor, and acceptor, the ternary and binary photovoltaics of P3HT: (Meissner and Wohrle, 1991; Meissner and Wohrle, 1991)-Phenyl C71 butyric acid methyl ester (PC71BM):supramolecule, P3HT:supramolecule, and PC71BM:supramolecule were prepared. The GQD-based nanostructures acted better than the CQD-based ones, originated from their thinner and disk-like nature, and the highest photovoltaic characteristics were detected in P3HT:PC71BM:GQD/P3HT nanofiber systems (14.06 mA cm−2, 0.70 V, 66.11%), leading to a performance of 6.50%. Thin films modified by crab-like GQD/P3HT short chain (5.47%), CQD/P3HT nanofiber (4.56%), and semicrab-like CQD/P3HT short chain (3.46%) nanostructures also reflected the high-quality devices. The systems manipulated by the crab/semicrab-like (668 and 462 Ω.cm2) and decorated fibrillar (553 and 395 Ω.cm2) nanostructures demonstrated the faster electron transport and, thereby the lower carrier recombination. Even the well-designed supramolecules of GQD/P3HT nanofiber and crab-like GQD/P3HT short chain led to the low-quality binary photovoltaics (3.68% and 2.29%) with respect to corresponding ternary systems. When the QDs and their associated nano-hybrids were employed as the electron donors, the weakest cells were fabricated and the highest efficacy was 2.01% for PC71BM:GQD/P3HT.

Lead-free and electron transport layer-free perovskite yarns: Designed for knitted solar fabrics

Highly flexible and Lead-free perovskite solar yarns, based on methylammonium tin mixed halide- Polyvinylpyrrolidone (PVP) composite nanofibers doped with [6,6]-Phenyl C61 butyric acid methyl ester (PC61BM), as the light harvesters are reported. The photoactive nanofiber layer of the solar yarn featured an optical bandgap of 1.65 eV, with a remarkable light absorption capacity > 90% in the wavelength range of 300–550 nm, outstanding flexibility, and an impressive charge carrier lifetime of 278 ns which rises to 300 ns upon doping with PC61BM. These photoactive nanofibers are directly electrospun on top of poly(3-hexylthiophene-2,5-diyl) ‘P3HT’, as the hole transporting layer, which was coated on a multi-filament carbon fiber yarn. The resulting yarn is twisted with a commercial silver yarn, serving as the positive electrode. The ensuing fiber-shaped solar device exhibits a maximum power conversion efficiency of 5.34% which is increased to 7.49% upon doping the photoactive layer with 0.17% PC61BM. A knitted solar fabric from the novel solar yarn with 45-mm × 35-mm active area presented a maximum power density of 1.21 mWcm−2 under 1 sun (1000 Wm−2) solar illumination.

The effect of polymer concentration in chloroform on P3HT:PCBM nanoparticulate organic photovoltaic device performance

Investigations about the effect of concentration of polymer (1:1 Poly (3-hexylthiophene) (P3HT):phenyl C61 butyric acid methyl ester (PCBM)) in chloroform have been performed. Six different concentrations varying from 36 mg/ml to 179 mg/ml, were used to prepare P3HT:PCBM nanoparticulate organic photovoltaic (NP-OPV) devices. Using Dynamic Light Scattering (DLS), KLA-Tencor Alpha Step 500 profilometer, UV-visible spectroscopy (UV-Vis), we analyze and optimize the concentration of polymer in chloroform in producing NP-OPV devices. Higher concentration resulting in a bigger size of nanoparticle and thicker thin film we have, so that affects the efficiency of NP-OPV devices. In this investigation, the highest efficiency was achieved when using a concentration of 54 mg/ml.