Photocurrent Generation from Porphyrin/Fullerene Complexes Assembled in a Tethered Lipid Bilayer

Abstract

A modular photocurrent generation system, based on amphiphilic porphyrin and fullerene species assembled in a tethered lipid bilayer matrix, is reported here. The key findings are (1) the amount of photoactive species can be quantitatively controlled in each leaflet of the bilayer and (2) the sequential formation of the bilayer allows a directional organization of these agents on electrodes. Photocurrent generation from seven differently configured photoactive bilayers is studied, which reveals several critical factors in achieving efficient photoinduced electron transfer across lipid membranes. Detailed fluorescence characterization is performed on porphyrin samples either in liposomes or surface-tethered bilayers; and the observed fluorescence quenching is correlated with photocurrents generated from the electrode-immobilized lipid films. The potential usefulness of this lipid-based approach is discussed in connection to several existing molecular photovoltaic systems.

Amino acids, peptides and proteins

“…Figure 3 a compares the anodic/cathodic photocurrents obtained from hybrid bilayers that contain a concentration of 2 mol % ZnP‐DOPE in the top POPC layer. As discussed in our previous work,10 these photocurrents result from photoinduced electron‐transfer processes between excited porphyrin and sacrificial redox agents in solution. Here in the anodic process, a photocurrent of approximately 130 nA cm −2 was generated from the bilayers with the C 12 SAM as the underlayer, whereas a lower current of approximately 50 nA cm −2 was obtained if the underlying SAM was C 10 F 17 SH instead.…”

“…The SAM‐modified gold substrates were carefully rinsed with ethanol and deionized water, dried in argon, and immediately assembled in homemade Teflon cells to be used either for impedance analysis or photoelectrochemical measurements. Preparation of liposome samples that contained fullerenes8 or porphyrin‐conjugated lipids10 has been reported previously. Briefly, POPC and either of the photoagents (2 mol %) were mixed in chloroform and thoroughly dried.…”

Aqueous-Based Photocurrent Generation by Fluorescence Resonance Energy Transfer between Conjugated Oligoelectrolytes and Erythrosin B

“…13 또한 광감지제와 플러렌(fullerene, C60)과 같은 전자 수용체 를 전극 기판에 대해 직각이 되도록 인지질 이중층 내부에 위치시킬 경우 광감지제에 의해 흡수된 에너지가 전자 수용 체와 전극에 순차적으로 전달되어 생성되는 광전류의 양을 증대시킬 수 있음이 보고되었다. [14][15][16][17] 본 연구진은 형광공명에너지전달(Förster resonance energy transfer 또는 fluorescence resonance energy transfer, FRET) 현상이 수용액 기반 광전류 생성 장치의 효율을 효과적으로 증대시킴을 최근 보고한 바 있다. 18 양이온성 전도성 올리고전 해질(conjugated oligoelectrolyte)인 4,4'-bis(4'-(N,N-bis (6''(N,N,Ntrimethylammonium)…”

Electrochemical Impedance Spectroscopy as a Convenient Tool to Characterize Tethered Bilayer Membranes

“…Those areas include structure-function studies of proteins in membranes, including membrane damage processes inflicted by pore-forming proteins and peptides [2]. The tBLMs are suggested as phospholipid bilayer biosensors capable of detecting protein interactions with toxins, pathogen microorganisms, or biosensors containing membrane-bound enzymes [3], biophotovoltaics [4] as well as other biotechnology applications [5]. Electrode-supported membranes are regarded as a convenient experimental platform allowing the application of different surface-sensitive techniques, including spectroscopy, neutron reflectometry [6,7], and electrochemical methods [8].…”