Herein, we studied the use of two different Self Assembled Monolayers (SAMs) made of semiconductor hole transport organic molecules to replace the most common p-type contact, PEDOT:PSS, in PiN methyl ammonium lead iodide perovskite solar cells (PSCs).

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Novel hole‐transporting dendrimeric molecules containing dioctylfluorene, spirobi(fluorene) and spiro(cylododecane‐fluorene) as the core unit and different numbers of carbazole and thiophene moieties as the peripheral groups are synthesized. All the dendrimers are characterized by 1H NMR, 13C NMR, FTIR, UV–vis, PL spectroscopy, and MALDI‐TOF. They are thermally stable with high glass transition and decomposition temperatures and exhibit chemically reversible redox processes. They are used as the hole‐transporting layer (HTL) material for multilayer organic light emitting diodes (OLEDs) with a low turn‐on voltage of around 2.5 V and a bright green emission with a maximum luminance of around 25400 cd m−2.

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a b s t r a c t 4-[(3-Methylphenyl)(phenyl)amino]benzoic acid (MPPBA) was synthesized in order to facilitate the hole-injection in Organic Light Emitting Diodes (OLED). MPPBA was applied to form self-assembled monolayer (SAM) on indium tin oxide (ITO) anode to align energy-level at the interface between organic semiconductor material (TPD) and inorganic anode (ITO) in OLED devices. The modified surface was characterized by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and Kelvin probe force microscopy (KPFM). KPFM was used to measure the surface potential and work function between the tip and the ITO surface modified by SAM technique using MPPBA. The OLED devices (ITO/MPPBA/TPD/Alq 3 /Al) fabricated with SAM-modified ITO substrates showed lower turn-on voltages and enhanced diode current compare to the OLED devices fabricated with bare ITO substrates.Crown

A novel electroactive spirocyclododecylfluorene monomer named 2,7-bis(carbazol-9-yl)-9,9 0 -spiro[cyclododecane-1,9 0 -fluorene] (SFC) was synthesized and electrochemically polymerized to give a very stable multi-electrochromic polymer (poly-SFC). Two separate oxidation processes were observed for both SFC monomer and poly-SFC that carries two carbazole units. The polymeric film of poly-SFC was coated onto ITO/glass surface, and it shows different colors (transparent, yellowish green, green, and dark green) upon stepwise oxidations. An electrochromic device based on poly-SFC was assembled in the sandwich cell configuration of ITO/poly-SFC// gel electrolyte//PEDOT/ITO. Poly-SFC exhibits 90% of transparency at neutral state and a high contrast ratio (DT ¼ 58% at 800 nm). This device constructed from it represents a response time of about 1 s, high coloration efficiency (1377 cm 2 C -1 ) and retained its performance by 96.4% even after 1000 cycles. Exhibiting high transparency at neutral state, reversible redox behavior, resistance to overoxidation, and especially high contrast ratio at near IR region can make poly-SFC be useful and promising candidate for electrochromic applications despite having a relatively slow response time. V C 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 49: 333-341, 2011