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Energy sustainability and interconnectivity are the two main pillars on which cutting-edge architecture is based and require the realization of energy and intelligent devices that can be fully integrated into buildings, capable of meeting stringent regulatory requirements and operating in real-world conditions. Luminescent solar concentrators, particularly those based on near-infrared emitting reabsorption-free quantum dots, are considered good candidates for the realization of semi-transparent photovoltaic glazing, but despite important advances in optical property engineering strategies, studies of finished devices suitable for real-world operation are still lacking. In this paper, the first example of a fully assembled quantum dot luminescent solar concentrator-based photovoltaic glazing is demonstrated that meets all international standards for photovoltaic and building elements. It is also shown that these devices are capable of functioning as efficient Visible Light Communication (VLC) receivers even under full sunlight, thus combining energy and wireless connectivity functions in a realistic solution for smart, sustainable buildings.

Lead halide perovskite nanocrystals (LHP-NCs) embedded in polymeric hosts are gaining attention as scalable and low-cost scintillation detectors for technologically relevant applications. Despite rapid progress, little is currently known about the scintillation properties and stability of LHP-NCs prepared by the ligand assisted reprecipitation (LARP) method, which allows mass scalability at room temperature unmatched by any other type of nanostructure, and the implications of incorporating LHP-NCs into polyacrylate hosts are still largely debated. Here, we show that LARP-synthesized CsPbBr3 NCs are comparable to particles from hot-injection routes and unravel the dual effect of polyacrylate incorporation, where the partial degradation of LHP-NCs luminescence is counterbalanced by the passivation of electron-poor defects by the host acrylic groups. Experiments on NCs with tailored surface defects show that the balance between such antithetical effects of polymer embedding is determined by the surface defect density of the NCs and provide guidelines for further material optimization.

We report a colloidal synthesis of blue emissive, stable cube-shaped CsPbBr3 quantum dots (QDs) in the strong quantum confinement regime via dissolution–recrystallization starting from pre-syntesized (KxCs1–x)4PbBr6 nanocrystals which are then reacted with PbBr2. This is markedly different from the known case of Cs4PbBr6 nanocrystals that react within seconds with PbBr2 and get transformed into much larger, green emitting CsPbBr3 nanocrystals. Here, instead, the conversion of (KxCs1–x)4PbBr6 nanocrystals to CsPbBr3 QDs occurs in a time span of hours, and tuning of the QD size is achieved by adjusting the concentration of the precursors. The QDs exhibit excitonic features in optical absorption that are tunable in the 420–452 nm range, accompanied by blue photoluminescence with quantum yield around 60%. Detailed spectroscopic investigations in both the single and multiexciton regime reveal the exciton fine structure and the effect of Auger recombination of these CsPbBr3 QDs, confirming theoretical predictions for this system.

Lead halide perovskite nanocrystals (LHP-NCs) embedded in polymeric hosts are gaining attention as scalable and low-cost scintillation detectors for technologically relevant applications. Despite rapid progress, little is currently known about the scintillation properties and stability of LHP-NCs prepared by the ligand assisted reprecipitation (LARP) method, which allows mass scalability at room temperature unmatched by any other type of nanostructure, and the implications of incorporating LHP-NCs into polyacrylate hosts are still largely debated. Here, we show that LARP-synthesized CsPbBr3 NCs are comparable to particles from hot-injection routes and unravel the dual effect of polyacrylate incorporation, where the partial degradation of LHP-NCs luminescence is counterbalanced by the passivation of electron-poor defects by the host acrylic groups. Experiments on NCs with tailored surface defects show that the balance between such antithetical effects of polymer embedding is determined by the surface defect density of the NCs and provide guidelines for further material optimization.

The use of scintillators for the detection of ionizing radiation is a critical aspect in many fields, including medicine, nuclear monitoring, and homeland security. Recently, lead halide perovskite nanocrystals (LHP-NCs) have emerged as promising scintillator materials. However, the difficulty of affordably upscaling synthesis to the multigram level and embedding NCs in optical-grade nanocomposites without compromising their optical properties still limits their widespread use. In addition, fundamental aspects of the scintillation mechanisms are not fully understood, leaving the scientific community without suitable fabrication protocols and rational guidelines for the full exploitation of their potential. In this work, we realize large polyacrylate nanocomposite scintillators based on CsPbBr3 NCs, which are synthesized via a novel room temperature, low waste turbo-emulsification approach, followed by their in situ transformation during the mass polymerization process. The interaction between NCs and polymer chains strengthens the scintillator structure, homogenizes the particle size distribution and passivates NC defects, resulting in nanocomposite prototypes with luminescence efficiency >90%, exceptional radiation hardness, 4800 ph/MeV scintillation yield even at low NC loading, and ultrafast response time, with over 30% of scintillation occurring in the first 80 ps, promising for fast-time applications in precision medicine and high-energy physics. Ultrafast radioluminescence and optical spectroscopy experiments using pulsed synchrotron light further disambiguate the origin of the scintillation kinetics as the result of charged-exciton and multiexciton recombination formed under ionizing excitation. This highlights the role of nonradiative Auger decay, whose potential impact on fast timing applications we anticipate via a kinetic model.

The use of scintillators for the detection of ionizing radiation is a critical aspect in many fields, including medicine, nuclear monitoring, and homeland security. Recently, lead halide perovskite nanocrystals (LHP-NCs) have emerged as promising scintillator materials. However, the difficulty of affordably upscaling synthesis to the multigram level and embedding NCs in optical-grade nanocomposites without compromising their optical properties still limits their widespread use. In addition, fundamental aspects of the scintillation mechanisms are not fully understood, leaving the scientific community without suitable fabrication protocols and rational guidelines for the full exploitation of their potential. In this work, we realize large polyacrylate nanocomposite scintillators based on CsPbBr3 NCs, which are synthesized via a novel room temperature, low waste turbo-emulsification approach, followed by their in situ transformation during the mass polymerization process. The interaction between NCs and polymer chains strengthens the scintillator structure, homogenizes the particle size distribution and passivates NC defects, resulting in nanocomposite prototypes with luminescence efficiency >90%, exceptional radiation hardness, 4800 ph/MeV scintillation yield even at low NC loading, and ultrafast response time, with over 30% of scintillation occurring in the first 80 ps, promising for fast-time applications in precision medicine and high-energy physics. Ultrafast radioluminescence and optical spectroscopy experiments using pulsed synchrotron light further disambiguate the origin of the scintillation kinetics as the result of charged-exciton and multiexciton recombination formed under ionizing excitation. This highlights the role of nonradiative Auger decay, whose potential impact on fast timing applications we anticipate via a kinetic model.

Luminescent solar concentrators (LSCs) are all-photonic, semitransparent solar devices with great potential in the emerging fields of building-integrated photovoltaics and agrivoltaics. Over the past decade, particularly with the advent of quantum dot (QD) LSCs, tremendous progress has been made in terms of photovoltaic efficiency and device size by increasing solar spectral coverage and suppressing reabsorption losses. Despite these advances in LSC design, the effects of environmental conditions such as rain, dust, and dirt deposits, which are ubiquitous in both urban and agricultural environments, on LSC performance have been largely overlooked. Here, we address these issues by systematically investigating the environmental effects on the solar harvesting and waveguiding capability of state-of-the-art QD-LSCs, namely, the presence of airborne pollutants (dust), water droplets, and dried deposits. Our results show that dust is unexpectedly insignificant for the waveguiding of the concentrated luminescence and only reduces the LSC efficiency through a shadowing effect when deposited on the outer surface, while dust accumulation on the inner LSC side increases the output power due to backscattering of transmitted sunlight. Water droplets, on the other hand, do not dim the incident sunlight, but are detrimental to waveguiding by forming an optical interface with the LSC. Finally, dried deposits, which mimic the evaporation residues of heavy rain or humidity, have the worst effect of all, combining shading and waveguide losses. These results are relevant for the design of application-specific surface functionalization/protection strategies real LSC modules.

Cesium lead halide perovskite nanocrystals of general formula CsPbX3 are having tremendous impact on a vast array of technologies requiring strong and tunable luminescence across the visible range and solutions processing. The development of plastic scintillators is just one of the many relevant applications. The syntheses are relatively simple but generally unsuitable to produce a large amount of material of reproducible quality required when moving from proof-of-concept scale to industrial applications. Wastes, particularly large amounts of lead-contaminated toxic and flammable organic solvents, are also an open issue. We describe a simple and reproducible procedure enabling the synthesis of luminescent CsPbX3 nanobricks of constant quality on a scale going from 0.12 to 8 g in a single batch. We also show complete recycling of the reaction wastes, leading to dramatically improved efficiency and sustainability.

The search for efficient, re-absorption-free scintillators has recently focused the attention on antimony-based halides, which exhibit largely Stokes shifted luminescence due to radiative recombination of excitons self-trapped (STE) in strongly Jahn–Teller distorted Sb3+ color centers. Here, the synthesis of a hybrid structure is reported with chemical formula (C13H14N3)3SbCl6 consisting of spatially isolated [SbCl6]3− octahedra separated by organic N,N'-diphenylguanidinium (Gua) molecules. The optical properties of this material are mainly determined by the inorganic component and are characterized by a pronounced Stokes shift of ≈1.3 eV and a room-temperature photoluminescence (PL) efficiency of up to 85%. Remarkably, highly efficient radioluminescence (RL) is observed with scintillation light yields of ≈2000 ph MeV−1 using both soft X-rays and a 124 keV gamma source. Temperature-dependent PL and RL measurements confirm the minor role of non-radiative channels, which are completely suppressed below 100 K. Thermally stimulated luminescence measurements suggest that the traps in Gua3SbCl6 crystals have a significantly large energy depth distribution below the absorbing state.

Questa tesi si concentra sul lavoro sperimentale nel campo della spettroscopia fondamentale di nanocristalli luminescenti avanzati per applicazioni optoelettroniche, nell'ambito dei materiali per l'energia. In primo luogo, descriverò lo sviluppo di uno strumento per l'analisi avanzata di tali nanoparticelle, ossia la Spettroscopia a Singola Particella (SPS) . Questa tecnica ha il potenziale di analizzare le proprietà ottiche a livello di singolo nanocristallo per comprendere meglio l'influenza della moltitudine di nanodifferenze che si perdono nelle misure di spettroscopia d'insieme; queste informazioni, infatti, diventano sempre più rilevanti man mano che le strategie sintetiche diventano sempre più sofisticate e all'avanguardia. Inoltre, è possibile studiare il processo di antibunching in una potenziale sorgente a singolo emettitore, elemento chiave per lo sviluppo di tecnologie quantistiche. Questo tipo di misura non è mai stato eseguito nel nostro laboratorio, quindi ho iniziato da zero a progettare e mettere insieme l'intero sistema. La realizzazione sperimentale di questo set-up è piuttosto complessa per diversi motivi tra cui il livello di intensità luminosa estremamente basso, la criticità dell'allineamento al di sotto del limite di diffrazione e dei requisiti di risoluzione temporale per le misure di correlazione. Il primo capitolo sarà dedicato allo studio di un progetto efficace e all'ottimizzazione di un set-up SPS, passando attraverso le prove e gli errori che hanno portato alla geometria finale. Siamo riusciti a misurare le proprietà ottiche di nanoplatelets colloidali core-shell a livello di singola particella, ottenendo risultati interessanti e dimostrando l'efficacia del set-up costruito. Parallelamente alla realizzazione di questo set-up, il mio lavoro di ricerca si è focalizzato sullo studio fondamentale di alcune nanostrutture dal design innovativo da studiare, in prospettiva, col sistema SPS. Questi nuovi materiali sono stati descrit, This thesis focuses on experimental work in the field of fundamental spectroscopy of advanced luminescent nanocrystals for optoelectronic applications, in the wider context of new materials for energy. First, I will describe the development of a powerful tool for the advanced analysis of such nanoparticles, namely Single Particle Spectroscopy (SPS). This technique has the potential to analyze optical properties at the single nanocrystal level to better understand the influence of the multitude of nano-differences that are lost in ensemble spectroscopy measurements; in fact, this information becomes increasingly relevant as synthetic strategies become more sophisticated and state-of-the-art. In addition, it is possible to study the antibunching process in a potential single-emitter source, a key element in the development of quantum technologies. This type of measurement has never been performed in our laboratory, so I started from scratch to design and put together the whole system. The experimental implementation of this set-up is quite complex for several reasons including the extremely low light intensity level, the criticality of the alignment below the diffraction limit and the time resolution requirements for correlation measurements. The first chapter will be devoted to the study of an effective design and optimization of an SPS set-up, going through the trials and errors that led to the final geometry. We were able to measure the optical properties of core-shell colloidal nanoplatelets at the single-particle level, obtaining peculiar results and demonstrating the effectiveness of the constructed set-up. Parallel to the construction of this set-up, my research work focused on the fundamental study of some nanostructures with novel designs to be measured prospectively with the SPS system. These new materials have been described in Chapter 2 and Chapter 3; in particular, Chapter 2 focuses on the cutting-edge progress of the already well-known lead halide perovs

Fluorescent concentrators (FCs) have been recently proposed as optical condensers for visible light communications (VLC) and optical wireless communication (OWC) receivers, with advantages over conventional optical stages in terms of optical gain and field of view (FoV). However, the use of FC-based receivers in real-world scenarios is hampered by the need for large resilience of the involved chromophores to sunlight exposure, and availability of large-area FC substrates with suitable optochemical properties. This paper presents an innovative OWC system, based on a high-power blue LED and a large-area FC-based on CuInS2 quantum dots (Q-Dots) as receiving optical stage. A thorough characterization of the FC material in terms of conversion efficiency, temporal response, and FoV is provided, along with a full set of outdoor measurements. The combination of the Q-Dots fluorophores chemico-physical properties with the strong DC rejection granted by the design receiver stage allows error-free VLC link distances up to 60 m and baud rates up to 1 Mb/s. This work represents the first demonstration of long-range VLC links under strong solar irradiance using large-area FC antennas and paves the way to deployment of long-range free-space optical links with minimal susceptibility to misalignments and pointing instabilities between receiver and transmitter.