光致界面电荷转移

工作汇报
专业：环境工程姓名:孙明明日期：2014/11/29

光致界面电荷转移的机理
金属功函数Wm：把金属中电子从费米能级EFm逸出到真空E0中所需的最小能量称为金属的功函数半导体功函数Ws：把E0与费米能级EFS之差称为半导体的功函数接触电势差：在交界面,电子会从功函数小的材料转移到功函数大的材料中，从而前者带上正电荷，后者带上负电荷，这样就产生

了接触电势差。
费米能级：在固体物理学中，一个由无相互作用的费米子组成的系统的费米能,表示在该系统中加入一个粒子引起的基态能量的最小可能增量。费米能:亦可等价定义为在绝对零度时，处于基态的费米子系统的化学势，

或上述系统中处于基态的单个费米子的最高能量。费米能
学的核心概念之一。

是凝聚态物理

表面电势:它是指由于两相界面区偶极层的存在或自由电荷(离子或电子) 的不均匀分布而造成的两相之间的电势差。若规定某一相的内部的电势为零，则此差值即为另一相的表面电势，其数值等于把单位正电荷从表面外约10-4cm处通过界面移进相内所耗费的电势。由于这一过程不可避免地会涉及化学作用。所以表面电势虽有明确的物理意义，实际上却无法测量。本征半导体是一种完全没有杂质和缺陷的理想半导体材料。对于掺杂施主的半导体，导带电子是多数载流子，价带空穴是少数载流子，称为n型半导体。

对于掺杂受主的半导体，价带空穴是多数载流子，导带电子为少数载流
子，称为P型半导体。

本征激发：当半导体从外界获得一定的能量，受到激发，电子从价带顶端跃迁到导带底端，而产生出自由电子和自由空穴的现象。
本征激发的容易程度受到禁带宽度的影响。

透明导电玻璃

透明导电玻璃

光致界面电荷转移的机理

文献
A study of light-induced charge transfer at interface of copper tetrasulphonatophalocynine molecular films and p-Si(III)
在磺化酞菁铜超分子膜和p-Si(III)的界面间光诱导电荷转移的研究
?

Thin Solid Films

Abstract
?

CuTsPc supramolecular films and CuTsPc LB films with space in the lipid chain were prepared on p-Si(III) using the LB technique. The surface photovoltage spectra of both film systems were measured for the first time. It was found that the surface photovoltaic effect of the film systems was at a maximum when only one monolayer of CuTsPc molecules was modified on p-Si(III). Our experiments indicated that only the first CuTsPc monolayer adjacent to the semiconductor plays a key role in the light-induced interfacial charge transfer.

?

?

1. Introduction
much research has been devoted to the sensitization of semiconductor materials by organic dye films and their

application in a variety of solid sta

te devices.
It is worth noting that Honda and coworkers used LB film

containing chlorophyl to modify SnO2 photoanodes which had
exhibited a high quantum efficiency (25%) for photocurrent generation . This result suggests that the specific properties of LB films promise some novel effects in the sensitization of semiconductor materials.

?

Recently, our group successfully prepared a new kind of ultrathin CuTsPc molecular film which has some

characteristics of a one-dimensional conductor .
?

the supramolecular films and CuTsPc LB films with space in the lipid chain were prepared on p-Si(III), and the dependence of their photovoltaic response on the film thickness was studied by surface photovoltage

spectroscopy. It was found that only the first CuTsPc monolayer adjacent to
the p-Si(III) plays a key role in light-induced interfacial charge transfer.

2. Experimental
CuTsPc , methylarachidate (AME) , octadecylamine (C18NH2)

单层膜系统的制备:
C18NH2-AME (1:4) ，CuTsPc (pH 4.4) ，LB膜 Langmuir trough ， chloroform
After 20 min

the monolayer was transferred onto a silicon wafer

The wafer was dry and was immersed in a saturated BaCI2 aqueous
solution for about 20min.

The Ba2+ replaced Na+ near the sulphonateions ， thereby making the CuTsPc film more densely packed and insoluble in aqueous solutions.

The wafer was then washed with pure water and dried.

Finally, the wafer was washed in chloroform to produce the lipid-free monolayer on the wafer.

The multilayer supramolecular films were prepared by repeating the above steps.

CuTsPc

In order to protect the molecular films, a contactless measurement
method was used: a thin sheet of mica with a circular hole 7 mm in diameter was placed between the electrodes and the measured sample.

3. Results and discussion

?

表面光电压是固体表面的光生伏特效应 ,是光致电子跃迁的结果。 “光生伏特效应”（ Photovoltaic effect），简称“光伏效应”。光伏效应指光照使不均匀半导体或半导体与金属结合的不同部位之间产生电位差的现象。半导体的表面光伏效应是指：

?

?

半导体吸收光子后光生电子和空穴在自建电场的作用下分离并作
反向运动，产生光生电势的效应。它是各种半导体光电器件的基础。能够引起固体中光伏效应，包

括体生光伏效应，表面光伏效应，耗尽层光伏效应和反常光伏效
应。

As a comparison, we prepared CuTsPc LB multilayers with space in the lipid chain on p-Si(III), and measured their surface photovoltage spectra (Fig. 4). 作为比较，我们在p-Si上的脂质链的空间上制备磺化酞菁铜 LB多层膜，并测量其表面光电压谱（图4）。

?

The results support the aforementioned conclusions. Furthermore, the surface photovoltaic signal decreases more rapidly than in the free-lipid CuTsPc supramolecular film with increasing number of layers. It is obvious that the CuT

sPc monolayers are separated from each other by the lipid chain, which inhibits the carrier transport between monolayers. 该结果支持了上述结论。此外，表面光伏信号减小速度比

?

磺化酞菁铜超分子膜快。
很明显，磺化酞菁铜单层膜通过脂质链被彼此分开，抑制了单层之间的载流子的传输分开。