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In CdS nanocrystals, photoexcited holes rapidly become trapped at the particle surface. The dynamics of these trapped holes have profound consequences for the photophysics and photochemistry of these materials. Using a combination of transient absorption spectroscopy and theoretical modelling, we demonstrate that trapped holes in CdS nanorods are mobile and execute a random walk at room temperature. In CdS nanorods of non-uniform width, we observe the recombination of spatially separated electrons and trapped holes, which exhibits a t −1/2 power-law decay at long times. A one-dimensional diffusion–annihilation model describes the time-dependence of the recombination over four orders of magnitude in time, from one nanosecond to ten microseconds, with a single adjustable parameter. We propose that diffusive trapped-hole motion is a general phenomenon in CdS nanocrystals, but one that is normally obscured in structures in which the wavefunctions of the electron and trapped hole spatially overlap. This phenomenon has important implications for the oxidation photochemistry of CdS nanocrystals. Photoexcited holes in CdS nanocrystals rapidly trap to the surface and although they are integral to nanocrystal photophysics and photochemistry, their dynamics have remained elusive. Time-resolved spectroscopy and theoretical modelling have now revealed that trapped holes in CdS nanorods are mobile and undergo a random walk on the nanocrystal surface.

When an innovation is inspired by design, it transcends technology and utility. The design delights the user, seamlessly integrating the physical object, a service, and its use into something whole. A design-inspired innovation is so simple that it becomes an extension of the user. It creates meaning and a new language.

By applying a phase-modulation fluorescence approach to 2D electronic spectroscopy, we studied the conformation-dependent exciton coupling of a porphyrin dimer embedded in a phospholipid bilayer membrane. Our measurements specify the relative angle and separation between interacting electronic transition dipole moments and thus provide a detailed characterization of dimer conformation. Phase-modulation 2D fluorescence spectroscopy (PM-2D FS) produces 2D spectra with distinct optical features, similar to those obtained using 2D photon-echo spectroscopy. Specifically, we studied magnesium meso tetraphenylporphyrin dimers, which form in the amphiphilic regions of 1,2-distearoyl-sn-glycero-3-phosphocholine liposomes. Comparison between experimental and simulated spectra show that although a wide range of dimer conformations can be inferred by either the linear absorption spectrum or the 2D spectrum alone, consideration of both types of spectra constrain the possible structures to a \"T-shaped\" geometry. These experiments establish the PM-2D FS method as an effective approach to elucidate chromophore dimer conformation.

Technology strategy variables tend to predominate as predictors of survival in the fast-changing rigid disk drive industry. Building on these previous studies, we here test the hypothesis that the technological and market strategies of a new entrant are highly interrelated and that their joint effect plays an important role in a firm's probability of survival. In particular, we propose that firms that target new market segments with an architectural innovation will tend to be more successful than those that target existing markets or innovate in component technology, even after controlling for all the competing predictors of survival. This paper advances the existing literature on innovation by tracing the main technical elements of a dominant design in the rigid disk drive industry over time, and provides a much more rigorous definition of the concept of a dominant design than we have had in the past. We find the notion of first-mover advantage is not applicable in the rigid disk drive industry. Instead, we propose the idea of an entry-window tightly linked to the emergence of the dominant product design as defined.

The economic, population ecology and strategic perspectives on firm survival are here complemented by viewing the same phenomenon from the viewpoint of technology evolution as well. The hypothesis tested is that the competitive environment of an industry, and therefore the survival of firms in it, is substantially affected by the evolution of the technology on which it is based. Survival analysis is applied to data from six industries. The results show that by explicitly including technology as a dynamic and strategic variable our understanding of firms' survival potential and success can be enhanced.

The paper proposes methods to measure the performance of research and development in new product development. We frame these measures in the context of evolving product families in the technology-based firm. Our goal is to more clearly understand the dynamics of platform renewal and derivative product generation and their consequences for long-term success. We explore the utility of the proposed methods with data gathered from a large measurement systems manufacturer. We find that the methods and measures can help management assess the technological and market leverage achieved from the firm's present and past product platforms. This provides a foundation for transforming single-product, single-period planning processes into a multi-product, multi-period form that embraces the product family and the renewal of product architecture. The research also shows the need to integrate data from engineering, manufacturing, and sales organizations to produce information for managing the growth of the firm's product families.

The confluence of nanotechnology and biotechnology provides significant commercial opportunities. By identifying, classifying and tracking firms with capabilities in both biotechnology and nanotechnology over time, we analyse the emergence and evolution of the global nanobiotechnology industry.

Technological transitions are challenging, particularly for companies in mature industries. Incumbents are frequently blindsided by new technologies, fully missing opportunities to enter emerging markets early. While some established companies do possess the awareness and dexterity to become early adopters of new technologies, they typically lack the vision and the commitment to become leaders. Too often, they cling to the familiar, developing hybrid products that combine elements of the old and the new. The trouble is, hybrid strategies put even the best incumbent companies in a weak position when the market finally embraces the new technology. We call this the \"hybrid trap.\" The transition from internal combustion engines to electric vehicles demonstrates the dangers of hesitating to embrace the new. New markets are often enabled by technological change and exploited by minds that can envision futures that are far different from the status quo. More so, they are convinced that such a future must happen.

Looking back over the descriptions of industry evolution and of individual firms that have mastered generations of technological change, the idea of developing and balancing core competencies as the key to success seems more credible than many current management philosophies.