Performance improvement of MEH-PPV:PCBM solar cells using bathocuproine and bathophenanthroline as the buffer layers

In this work, bathocuproine （BCP） and bathophenanthroline （Bphen）, commonly used in small-molecule organic solar cells （OSCs）, are adopted as the buffer layers to improve the performance of the polymer solar cells （PSCs） based on poly（2-methoxy-5-（2-ethylhexyloxy）-1,4-phenylenevinylene） （MEH-PPV）： [6,6]-phenyl-C61-butyric acid methyl ester （PCBM） bulk heterojunction. By inserting BCP or Bphen between the active layer and the top cathode, all the performance parameters are dramatically improved. The power conversion efficiency is increased by about 70% and 120% with 5-am BCP and 12-nm Bphen layers, respectively, when compared with that of the devices without any buffer layer. The performance enhancement is attributed to BCP or Bphen （i） increasing the optical field, and hence the absorption in the active layer, （ii） effectively blocking the excitons generated in MEH-PPV from quenching at organic/aluminum （Al） interface due to the large band-gap of BCP or Bphen, which results in a significant reduction in series resistance （Rs）, and （iii） preventing damage to the active layer during the metal deposition. Compared with the traditional device using LiF as the buffer layer, the BCP-based devices show a comparable efficiency, while the Bphen-based devices show a much larger efficiency. This is due to the higher electron mobility in Bphen than that in BCP, which facilitates the electron transport and extraction through the buffer layer to the cathode.

Variations in Electroluminescence Spectra of Organic Light Emitting Diodes Containing Bathocuproine Layer

Electroluminescence （EL） of organic light emitting diodes （OLEDs） with a configtration of ITO/TPD/BC/Alq3/Mg-Ag, where TPD, BC and Alq3 represent N, N＇-diphenyl-N, N＇-bis （3-methylphenyl）-1,1＇-biphenyl-4,4＇-diamine, bathocuproine and tris（8-quinolinolato）aluminum（III）, respectively, was investigated in comparison with the photoluminescence （PL） of the individual organic layers. The EL spectra of the OLEDs were found to be much different from the PL spectra of the component multiple layer structure. Each organic layer made its contribution to the light emitted from the OLEDs. Their individual contributions were related to the field distribution across the device, which was in turn dependent on the thickness of each organic layer and the applied bias voltages. Consequently, the EL spectra of the OLEDs were observed to vary as the relative thickness of any organic layer was changed and as the bias voltage was alternated. The variation of the EL spectra of the device resulted in the easiness of achieving variable colors emitted by the device, from blue to green, and then to near white light.

Efficient fully blade-coated perovskite solar cells in air with nanometer-thick bathocuproine buffer layer

Fully printed perovskite solar cells(PSCs)were fabricated in air with all constituent layers,except for electrodes,deposited by the blade coating technique.The PSCs incorporated,for the first time,a nanometer-thick printed bathocuproine(BCP)hole blocking buffer using blade coating and deposited at relative humidity up to 50%.The PSCs with a p-i-n structure(glass/indium tin oxide(ITO)/poly(3,4-ethylenedioxythiophene)polystyrene sulfonate(PEDOT:PSS)/CH_(3)NH_(3)Pbl_(3)/[6,6]-phenyl-C_(61)-butyric acid methyl ester(PCBM)/BCP/Ag)delivered a maximum power conversion efficiency(PCE)of 14.9%on an active area of 0.5 cm^(2)when measured under standard test conditions.The PSCs with a blade coated BCP delivered performance of 10%and 63%higher(in relative terms)than those incorporating a spin coated BCP or without any BCP film,respectively.The atomic force microscopy(AFM)showed that blade coated films were more homogeneous and acted also as a surface planarizer leading to a reduction of roughness which improved BCP/Ag interface lowering charge recombination.The demonstration of 15%efficient devices with all constituent layers,including nanometer-thick BCP(〜10 nm),deposited by blade coating in air,demonstrates a route for industrialization of this technology.

Spectrophotometric Determination of Hydrogen Molecule by Redox Reaction of Ferric and Cupric Using Platinum Catalyzer

Simple methods for the determination of hydrogen molecule in water are developed. These methods are based on the redox reactions between metal ions such as ferric ion and cupric ion with hydrogen molecule in the presence of colloidal platinum. The released ferrous ion was developed with o-phenanthlorine, bathophenanthroline disul fonate and Ferrozine, on the other hand cuprous ion was developed with bathocuproinedisulfonate. In these methods, ferric ion is superior than cupric ion because of its sensitivity and stoichiometric reaction with hydrogen molecule. The hydrogen molecule proved to decompose hydroxy radical released from Fenton reaction by spectrofluorometry.

Boosting charge extraction and efficiency of inverted perovskite solar cells through coordinating group modification at the buffer layer/cathode interface

In inverted perovskite solar cells (PSCs),effective modification of the interface between the metalcathode and electron transport layer (ETL) is crucial forachieving high performance and stability. Herein, sulfonatedbathocuproine, commonly known as disodium bathocuproinedisulfonate (BCDS), was employed as a cathode buffer layerto address the interfacial issues at the [6,6]-phenyl-C61-butyricacid methyl ester (PCBM)/Ag interface. BCDS possesses theability to form coordinate bonds with Ag electrodes. Theutilization of the BCDS buffer layer enhanced the chargeextraction capability at the cathode interface whilesimultaneously achieving interfacial defect passivation,improving interfacial contact and increasing the built-in electricfield. Consequently, a power conversion efficiency (PCE) of25.06% was achieved. Furthermore, owing to the excellent filmforminguniformity of BCDS on PCBM, the stability of thedevice was also improved. After storage in dry air for morethan 2000 h, the device maintained 96% of its initial efficiency. This work underscores the remarkable potential of tailoringcoordination groups to enhance charge extraction efficiency at the ETL-cathode interface, unveiling a promising newfrontier in buffer layer development and performance optimization strategies for PSCs.