Photothermal conversion

The solar converter is positioned perpendicular to the sun s rays and absorbs heat per m2 at a rate. 

Finally, the converter emits black-body radiation at temperature T3  

The concentration factor C has been defined as the factor by which the incident solar radiation can be augmented. The ideal concentrator would compensate for the effect of the dilution factor/= 2.16 x 10-5, the value for our planet. The maximum concentration factor therefore is Cmax = 1 /f= 46,300. For an arbitrary value of C, Equation 17.32 has to be adapted according to 

Applying the same procedure for determining the maximum power characteristics as before and assuming moderately concentrated sunlight for which C = 389 [1], the solar energy efficiency w increases from 13% to somewhat above 60%. For the limit case of C = Cmax—all solar radiation is captured by our planet—w is close to 85%. 

Another way to improve on the solar energy efficiency w is to apply selective coating on the converter s absorbing and emitting surface. These coatings 

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Phototendering, dye-induced, 9 388-389 Photothermal conversion, of solar energy, 23 10... 

Maximum power is a concept introduced in Chapter 5. Appreciate its application in models for solar energy conversion to wind energy and photothermal conversion into electricity. 

Hosokawa, Y., Yashiro, M., Asahi, T. and Masuhara, H. (2001) Photothermal conversion dynamics in femtosecond and picosecond discrete laser etching of Cu-phfhalocyanine amorphous film analysed by ultrafast UV-VIS absorption spectroscopy. J. Photochem. Photobiol., A, 142, 197-207. 

Recently, the surface-modified gold nanorods were used as probe materials for surface-enhanced Raman scattering (SERS) [20, 21] and photoacoustic spectroscopy [50]. The SERS can give information on the vibrational modes of organic molecules on or near the gold nanorods, while photoacoustic spectroscopy is a sensitive way to detect photothermal conversion. These methods will open up new applications of gold nanorods as bioprobes. 

Chemical deposition can be anticipated for photothermal conversion applications in architecture. Nair et al. have also proposed the use of cuprous sulfide for this objective [47]. 

If effective absorbance and photothermal conversion efficiency are independent on the fluence, absorbed energy should be proportional to the latter and the slopes can be discussed simply in terms of thermal expansion coefficient of polymer Aims. The coefficient of linear expansion of rubber and glass states, ttg and Of, below and above glass-rubber transition temperature (Tg) of PMMA is (2.5-2.7) X 10- K and (5.6-5.S) X W K , respectively 3S). We consider that the one-dimensional expansion is induced along the perpendicular direction to the film, since polymer film outside the area irradiated by the excimer laser is of course hard. Then, the volume expansion could be replaced by the linear one along the thickness, so that corresponds to the change in the slope below... 

A commonly used strategy to prepare a liposome-based NIR-responsive vehicle, while optimizing liposome composition and structure to enhance circulation time and drug retention, is to incorporate Au nanostructures into the thermally sensitized liposome membranes. On NIR irradiation, Au nanostructures, such as nanoshells, nanorods or NPs, convert NIR light into heat, increasing the permeability of the liposome membrane via a photothermal conversion process. Finally, the anticancer drugs or genes are released from the liposomes. 

For evaluating photothermal agents, one of the key parameters is photothermal conversion efficiency. In this chapter, we first introduce the measurement method for photothermal conversion efficiency, which is discussed by an example from our group. Subsequendy,we summarize the progress of research on the four kinds of photothermal agents as well as the combination of PAT with other nanobiotechnology. The future prospects and challenges of this novel approach to cancer therapy are addressed in the final section of this chapter. 

Photothermal conversion efficiency (PCE) is an important parameter that describes the photothermal performances of materials. The classical calculation method for PCE developed by Roper et al. in 2007 has since been widely used in PCE calculation. ... 

The incorporation of light-sensitive nanoparticles can make them more sensitive to photothermal effects whereas PNIPAAm and its derivatives in their unmodified form could not have such function. In some studies, gold nanorod-embedded PNIPAAm hydrogels were prepared and their volume-phase transition behavior, induced by NIR laser irradiation utilizing the photothermal conversion characteristics of the nanorods. 

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