Moreover , the sio2 / tio2 composite thin film showed the lowest pl intensity due to a decrease in the recombination rate of photo - generated electrons and holes under uv light irradiation , which further confirmed the film with the highest photocatalytic activity at 700 c . when the calcination temperature was higher than 700 c , the decrease in photocatalytic activity was due to the formation of rutile and the sintering and growth of tio2 crystallites resulting in the decrease of surface area 同时，此时sio _ 2 / tio _ 2复合薄膜的荧光光谱显示最低的荧光强度，这表明此时薄膜中的光生电子和空穴的复合速率最低，因而更有利于物质的光催化降解。当热处理温度高于700时，武汉理工大学硕士学位论文薄膜的光催化活性下降，这是由于薄膜中晶相二氧化钦的烧结和成长导致样品的表面积下降以及金红石相的形成。
The initial activity of pt / tio2 was higher than that of tio2 because it restrained the recombination of electron and hole with supported pt , however the regenerated ability of the pt / tio2 was lower than that of tio2 . after the regeneration , the activity could come back to some 60 % of the original activity and the reaction activity declined rapidly . the reason might be that after regeneration on the surface of pt / tio2 the incomplete oxidation of h2s to produce s was enhanced Pt tio _ 2催化剂的初活性比单一的tio _ 2催化剂的初活性高，这是因为担载的贵金属抑制了电子与空穴的复合，但其再生性能比tio _ 2差，再生后活性只能恢复到初活性的约60 ，且反应活性迅速降低，这可能由于在再生后的pt tio _ 2表面上， h _ 2s通过不完全氧化生成s ~ 0的反应增强所致。
As the increasing of concentration , the host and guest interconverted , and the more the charge been transferred , the more the total energy decreased . finally , we deduce that the doping of rubrene in pvk just acting as traps in electroluminescent devices , and its trapping electrons arrested many cavities in pvk . and so , more pvk who did n ' t transport energy was concerned with trop and it makes less pvk was concerned with energy transfer in photoluminescent devices than in electroluminescent devices 基于光致发光和电致发光中pvk与rubrene发光强度的不同，我们对低掺杂时的电致发光和光致发光进行了比较，并提出：在电致发光中， rubrene的掺入在pvk链间相当于陷阱，其陷阱电子对pvk空穴的吸引，使一部分在光致发光中不参与能量传递的pvk参与了这种陷阱作用，使得在电致发光中不参与能量传递的pvk可能比光致发光中少。
In addition , when the electron - cavity pairs migrates to the films surface , there is adequate water to react with these electron - cavity pairs in good time . this not only reduces the composition probability of the electron - cavity pairs but also produces a large number of highly active hydroxyls that enhances the photocatalytic ability 紫外光照射下产生的电子-空穴对迁移到薄膜表面后，有足够的水分子及时地与空穴发生反应，不但减少了电子-空穴的复合机率，而且产生大量的强活性羟基，使薄膜的光催化性增强。
Firstly , we calculate variationally the binding energy and correlation energy of excitons in finite deep gaas - al0 . 33ga0 . 67as quantum wells . in the calculation , we consider the effect of effective mass and dielectric constant mismatch in the two materials . the results we obtained are basically conformed to the ones obtained from the previous theory and experiment 首先，我们计算了有限深gaas - al _ ( 0 . 33 ) ga _ ( 0 . 67 ) as量子阱中激子的束缚能，其中考虑到了阱和垒两种材料中电子和空穴的有效质量以及介电常数的失配影响，我们计算得到的激子的束缚能及相关能与前人的理论结果和实验结果基本上相符合。
Appling p - n graded heterojunction instead of abrupt one is studied deeply in theory , and the conclusion is that it will enhance the current injection ratio , decrease the built - in voltage , improve the quality of the crystal and it will not affect the confinement to the hole 在理论上提出在hb - led器件的dh结构中使用p - n结的渐变异质结替代现行的p - n突变异质结。分析采用异质结渐变方式将增加hb - led的电流注入比，减小内建电势，改善晶体质量，并且不影响p - n结对空穴的限制。
By analyzing their energy offset on the interfaces , we found that the introduction of ii - vi compounds replaces the original steep barrier with ladder - like barriers . the injection probability becomes the production of two injection probabilities through lower barriers and become larger than the original one . in chapter 5 we want to utilize the deeper , dynamical ( in addition of static ) properties of semiconductor to reinforce the luminescence of oel 为使类阴极射线发光同有机电致发光集成，我们设计了非对称结构al sioz mnppvn ， mn ppv中的发光是由于从sioz出来的电子和从ld注人的空穴的复合，而由于sioz中的电子的倍增过程，从sioz层出来的电子能量不是单一的，而有一个从低能到高能的分布。
As a result , the photocatalytic activities of htawoe / tio2 and htawo6 / cd0 . 8zn0 . 2s were superior to that of pristine samples , and they were greatly increased with co - doping pt particles in the interlayer . the photocatalytic activity of htawo6 / ( tio2 , pt ) was higher than tio2 ( p - 25 ) , which maybe due to that the surface area of htawo6 / ( tio2 , pt ) was 28 times as htawo6 ' s 当该材料受到光激发时，载流子有可能发生客体与客体及客体与基体间的迁移，降低电子和空穴的复合，从而有效提高半导体的光催化活性，且由于该材料易于回收重复利用，因此有望在环保领域得到广泛的应用。
